Cyclura nubila
Encyclopedia
Cyclura nubila, also known as the Cuban rock iguana, Cuban ground iguana, or Cuban iguana, is a species of lizard
of the iguana
family. It is the largest of the West Indian rock iguanas
(genus Cyclura), one of the most endangered groups of lizards. This herbivorous
species with red eyes, a thick tail, and spiked jowls is one of the largest lizards in the Caribbean
.
The Cuban iguana is distributed throughout the rocky southern coastal areas of mainland Cuba
and its surrounding islets with a feral
population thriving on Isla Magueyes, Puerto Rico
. It is also found on the Cayman Islands
of Little Cayman
and Cayman Brac
, where a separate subspecies
occurs. Females guard their nest sites and often nest in sites excavated by Cuban crocodile
s. As a defense measure, the Cuban iguana often makes its home within or near prickly-pear cacti.
Although the wild population is in decline because of predation
by feral
animals and habitat loss caused by human agricultural development, the numbers of iguanas have been bolstered as a result of captive-breeding and other conservation programs. Cyclura nubila has been used to study evolution and animal communication
, and its captive-breeding program has been a model for other endangered lizards in the Caribbean.
The Cuban rock iguana's generic
name Cyclura
is derived from the Ancient Greek
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. John Edward Gray
, the British zoologist
who first described the species in 1831 as Iguana (Cyclura) nubila or "Clouded Guana", gave it the specific name nubila, Latin
for "cloudy".
The closest relatives of Cyclura nubila are the Grand Cayman blue iguana
(Cyclura lewisi) and the Northern Bahamian rock iguana (Cyclura cychlura); phylogenetic analysis indicates that these three species diverged from a common ancestor three million years ago.
Cyclura nubila was previously considered to have three subspecies
, the Grand Cayman blue iguana (termed Cyclura nubila lewisi), the Lesser Caymans iguana (Cyclura nubila caymanensis
), and the nominate Cuban subspecies (Cyclura nubila nubila). This classification was revised after later mitochondrial DNA
analysis and research into the scalation patterns on the heads of Caribbean iguanid lizards (these patterns are unique by species and act as a "fingerprint" of sorts). The Grand Cayman blue iguana is now recognized as a separate species.a
The Cuban iguana is a large lizard, with an average body length of 40 centimetres (15.7 in) from snout to vent (the base of the tail). On rare occasions, individual males with lengths of 1.6 metres (5.2 ft) when measured from the snout to the tip of the tail have been recorded at the wildlife sanctuary within the Guantanamo Bay Naval Base
(GTMO), Cuba with females being two thirds that size. The species is sexually dimorphic
: males are much larger than females, and males have enlarged femoral pore
s on their thighs, which are used to release pheromone
s to attract mates and mark territory. The skin of male Cuban iguanas ranges in color from dark gray to brick red, whereas that of females is olive green with dark stripes or bands. In both sexes, limbs are black with pale brown oval spots and solid black feet. Young animals tend to be dark brown or green with faint darker striping or mottling in five to ten diagonal transverse bands on the body. These bands blend in with the body color as the iguana ages. Both sexes possess a dewlap
(skin hanging below the neck) and a row of spines
running down their back to their thick tail. Their heads and necks are short and stout, their teeth are solid and broad, and they have powerful jaw muscles. Their jowls, which grow larger as the animal ages, are covered in spiky protuberances called tubercles.
The Cuban iguana's eyes have a golden iris
and red sclera
. Cuban iguanas have excellent vision and the ability to detect shapes and movement at long distances. Sensory cells called "double cone
s" give them sharp color vision
and enable them to see ultraviolet
wavelengths. By seeking out locations with more ultraviolet sunlight to bask in, the Cuban iguana optimizes vitamin D
production. Cuban iguanas have poor low-light vision, because they have few rods
or photoreceptor cells. Like other iguanids, Cuban iguanas have a white photosensory organ on the top of their heads, called the parietal eye
. This "eye" has only a rudimentary retina and lens and cannot form images, but it is sensitive to changes in light and can detect movement.
), black mangrove (Avicennia germinans
), red mangrove (Rhizophora mangle
), olives, and various grasses. Aiding in the digestion of this high-cellulose
diet, colonies of nematode
s occupy 50% of the contents of Cuban iguanas' large intestine
s. Cuban iguanas occasionally consume animal matter, and individuals have been observed scavenging the corpses of birds, fish and crabs. Researchers on Isla Magueyes observed a single episode of cannibalism
in 2006 when an adult female iguana chased, caught, and ate a hatchling. The researchers wrote that the dense population on Isla Magueyes could have caused this incident.
Like other herbivorous lizards, the Cuban iguana is presented with a problem for osmoregulation
: plant matter contains more potassium
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike those of mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead, reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
. In the case of the Cuban iguana, which consumes large amounts of vegetation, these excess salt ions are excreted through the salt gland
in the same manner as in birds.
Mating occurs in May and June, and females lay single clutches of three to 30 eggs in June or July. According to field research, females deposit their eggs at the same nesting sites each year. The nests are built near each other as suitable nesting sites are becoming rare. On Cuba's Isla de Juventud, Cuban iguanas nest in pockets of earth exposed to the sun by Cuban crocodiles, after the crocodiles' eggs have hatched. These nests are separate from where adult iguanas live. In areas without crocodiles, the iguanas excavate nests in sandy beaches. At the San Diego Zoo, a female built a nest at the end of a long chamber she excavated in the sand. She stood near it for weeks, defending it by shaking her head and hissing at anyone who approached; this behavior demonstrated that Cuban iguanas guard their nest sites. The hatchlings spend several days to two weeks in the nest chamber from the time they hatch to the time they emerge from the nests; dispersing individually after emergence.
Although Cuban iguanas typically remain still for long periods of time and have a slow lumbering gait due to their body mass, they are capable of quick bursts of speed for short distances. Younger animals are more arboreal and will seek refuge in trees, which they can climb with great agility. The animal is a capable swimmer and will take to nearby water if threatened. When cornered they can bite and lash their tails in defense.
at Guantánamo Bay has been estimated at 2,000 to 3,000 individuals, and the animals are treated well and protected by US forces stationed at the base. An unusual incident occurred when a detainee in the prison assaulted a guard with a bloody tail torn from a Cuban iguana in May 2005.
The subspecies, Cyclura nubila caymanensis, is endemic to the "Sister Islands" of Little Cayman
and Cayman Brac
. The population on Cayman Brac is less than 50 of these animals and Little Cayman supports 1,500. A feral population of C. n. caymanensis has been established on Grand Cayman
.
The Cuban iguana makes its burrow near cacti or thistles, sometimes even within the cactus itself. These thorny plants offer protection and their fruit and flowers offer the iguanas food. In areas without cacti, the lizards make their burrows in dead trees, hollow logs, and limestone crevices.
In the mid-1960s a small group of Cuban iguanas was released from a zoo on Isla Magueyes
, southwest of Puerto Rico
, forming an independent free-ranging feral population. As of 2000, there has been talk of removing or relocating this population of iguanas by the US Department of Interior. This feral population is the source for 90% of the captive Cuban iguanas held in private collections and was the source for part of a study on animal communication and evolution conducted by Emilia Martins, a biologist at Indiana University
.
Martins' study compared the head-bob displays from the source population on Cuba with these animals on Isla Magueyes. The durations and pauses were longer by as much as 350% in the feral population. In comparison, the blue iguana of Grand Cayman's head-bob displays differed from those of the animals on Cuba by only about 20%. The rapid change in display structure between the colony of animals on Isla Magueyes and those on Cuba illustrated the potential of small founding population size as a catalyst to evolution with regard to communication
or display. In this case the difference was by only six generations at most.
The Cuban iguana is well-established in public and private collections. Many zoological parks and private individuals keep them in captive breeding program
s, minimizing the demand for wild-caught specimens for the pet trade
. Cuban iguanas are listed as "vulnerable" on the IUCN Red List
. The total population in Cuba is estimated at between 40,000 and 60,000 individuals, and the feral population on Isla Magueyes is estimated at over 1,000. According to Allison Alberts, Chief Conservation Officer of the San Diego Zoo
and lead researcher in Cuba, among the many wildlife species at GTMO, "The Cuban Iguana is one of the largest, undoubtedly the most visible, and certainly the most charismatic. It seems that no one completes a tour of duty at GTMO without getting to know these prehistoric-looking giants."
In a round-about way, the Cuban iguana's status under the US Endangered Species Act
made its way into US jurisprudence. In the fall of 2003, attorney
Tom Wilner needed to persuade the justices of the US Supreme Court to take the case of a dozen Kuwait
i detainees being held in isolation in Guantanamo Bay, Cuba, without charges, without a hearing and without access to a lawyer. According to Peter Honigsberg, a professor of law at the University of San Francisco, Wilner unsuccessfully made two arguments before the Court to hear his case; in his third argument he changed tactics by mentioning US law and the Cuban iguana. Wilner argued, "Anyone, including a federal official, who violates the Endangered Species Act
by harming an iguana at Guantanamo, can be fined and prosecuted. Yet the government argues that US law does not apply to protect the human prisoners there". According to Honigsberg, the Supreme Court agreed to hear the case because of this argument.
, the Hicacos Peninsula
, or Cayo Largo, areas where it was found in great numbers some 30 to 40 years ago.
As opposed to other West Indian islands where iguanids are found, consumption of iguana meat is not widespread in Cuba. Certain fishing communities do practice it for subsistence, but for the most part the animal is not eaten by Cubans. According to naturalist Thomas Barbour
, this is based on unfounded superstitious beliefs which suggest that the iguanas emit a dark fluid reminiscent of the black vomit of yellow fever
victims when they are killed. One of the reasons for their decline is habitat destruction
caused by the overgrazing of farm animals, housing development, and the building of tourist resorts on the beaches where the animals prefer to build their nests. Populations of iguanas suffer by the direct predation of introduced
animals such as rats, cats, and dogs. Feral hogs are responsible for destroying many iguana nest sites which they dig up for eggs. Ant predation of iguana eggs is another threat to the species.
In 1993 the San Diego Zoo
experimentally tested the utility of a "head-starting" program for newly hatched Cuban iguanas with funding from the National Science Foundation's Conservation and Restoration Biology Program. "Head-starting" is a process by which the Cuban iguana's eggs are hatched in an incubator and the animals are protected and fed for the first 20 months of their lives. The purpose is to get the animals to a size where they are more capable of fleeing from or fighting off predators. This technique was originally used to protect hatchling sea turtles, Galapagos land iguana
s, and Ctenosaura bakeri on the island of Utila
, but Alberts used it for the first time on a Cyclura species with the Cuban iguana. The purpose was not only to help the Cuban iguana population, but to test the overall effectiveness of headstarting as a conservation strategy for more critically endangered species of Cyclura.
The strategy proved successful, according to Alberts, when the released head-started iguanas reacted to predators, foraged for food, and behaved like their wild-born counterparts. This strategy has been implemented with great success with other critically endangered species of Cyclura and Ctenosaura
throughout the West Indies and Central America
, notably the Jamaican iguana, Grand Cayman blue iguana, Ricord's iguana
, Allen Cays iguana
, San Salvador iguana, and Anegada iguana
.
of the iguana
family. It is the largest of the West Indian rock iguanas
(genus Cyclura), one of the most endangered groups of lizards. This herbivorous
species with red eyes, a thick tail, and spiked jowls is one of the largest lizards in the Caribbean
.
The Cuban iguana is distributed throughout the rocky southern coastal areas of mainland Cuba
and its surrounding islets with a feral
population thriving on Isla Magueyes, Puerto Rico
. It is also found on the Cayman Islands
of Little Cayman
and Cayman Brac
, where a separate subspecies
occurs. Females guard their nest sites and often nest in sites excavated by Cuban crocodile
s. As a defense measure, the Cuban iguana often makes its home within or near prickly-pear cacti.
Although the wild population is in decline because of predation
by feral
animals and habitat loss caused by human agricultural development, the numbers of iguanas have been bolstered as a result of captive-breeding and other conservation programs. Cyclura nubila has been used to study evolution and animal communication
, and its captive-breeding program has been a model for other endangered lizards in the Caribbean.
The Cuban rock iguana's generic
name Cyclura
is derived from the Ancient Greek
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. John Edward Gray
, the British zoologist
who first described the species in 1831 as Iguana (Cyclura) nubila or "Clouded Guana", gave it the specific name nubila, Latin
for "cloudy".
The closest relatives of Cyclura nubila are the Grand Cayman blue iguana
(Cyclura lewisi) and the Northern Bahamian rock iguana (Cyclura cychlura); phylogenetic analysis indicates that these three species diverged from a common ancestor three million years ago.
Cyclura nubila was previously considered to have three subspecies
, the Grand Cayman blue iguana (termed Cyclura nubila lewisi), the Lesser Caymans iguana (Cyclura nubila caymanensis
), and the nominate Cuban subspecies (Cyclura nubila nubila). This classification was revised after later mitochondrial DNA
analysis and research into the scalation patterns on the heads of Caribbean iguanid lizards (these patterns are unique by species and act as a "fingerprint" of sorts). The Grand Cayman blue iguana is now recognized as a separate species.a
The Cuban iguana is a large lizard, with an average body length of 40 centimetres (15.7 in) from snout to vent (the base of the tail). On rare occasions, individual males with lengths of 1.6 metres (5.2 ft) when measured from the snout to the tip of the tail have been recorded at the wildlife sanctuary within the Guantanamo Bay Naval Base
(GTMO), Cuba with females being two thirds that size. The species is sexually dimorphic
: males are much larger than females, and males have enlarged femoral pore
s on their thighs, which are used to release pheromone
s to attract mates and mark territory. The skin of male Cuban iguanas ranges in color from dark gray to brick red, whereas that of females is olive green with dark stripes or bands. In both sexes, limbs are black with pale brown oval spots and solid black feet. Young animals tend to be dark brown or green with faint darker striping or mottling in five to ten diagonal transverse bands on the body. These bands blend in with the body color as the iguana ages. Both sexes possess a dewlap
(skin hanging below the neck) and a row of spines
running down their back to their thick tail. Their heads and necks are short and stout, their teeth are solid and broad, and they have powerful jaw muscles. Their jowls, which grow larger as the animal ages, are covered in spiky protuberances called tubercles.
The Cuban iguana's eyes have a golden iris
and red sclera
. Cuban iguanas have excellent vision and the ability to detect shapes and movement at long distances. Sensory cells called "double cone
s" give them sharp color vision
and enable them to see ultraviolet
wavelengths. By seeking out locations with more ultraviolet sunlight to bask in, the Cuban iguana optimizes vitamin D
production. Cuban iguanas have poor low-light vision, because they have few rods
or photoreceptor cells. Like other iguanids, Cuban iguanas have a white photosensory organ on the top of their heads, called the parietal eye
. This "eye" has only a rudimentary retina and lens and cannot form images, but it is sensitive to changes in light and can detect movement.
), black mangrove (Avicennia germinans
), red mangrove (Rhizophora mangle
), olives, and various grasses. Aiding in the digestion of this high-cellulose
diet, colonies of nematode
s occupy 50% of the contents of Cuban iguanas' large intestine
s. Cuban iguanas occasionally consume animal matter, and individuals have been observed scavenging the corpses of birds, fish and crabs. Researchers on Isla Magueyes observed a single episode of cannibalism
in 2006 when an adult female iguana chased, caught, and ate a hatchling. The researchers wrote that the dense population on Isla Magueyes could have caused this incident.
Like other herbivorous lizards, the Cuban iguana is presented with a problem for osmoregulation
: plant matter contains more potassium
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike those of mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead, reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
. In the case of the Cuban iguana, which consumes large amounts of vegetation, these excess salt ions are excreted through the salt gland
in the same manner as in birds.
Mating occurs in May and June, and females lay single clutches of three to 30 eggs in June or July. According to field research, females deposit their eggs at the same nesting sites each year. The nests are built near each other as suitable nesting sites are becoming rare. On Cuba's Isla de Juventud, Cuban iguanas nest in pockets of earth exposed to the sun by Cuban crocodiles, after the crocodiles' eggs have hatched. These nests are separate from where adult iguanas live. In areas without crocodiles, the iguanas excavate nests in sandy beaches. At the San Diego Zoo, a female built a nest at the end of a long chamber she excavated in the sand. She stood near it for weeks, defending it by shaking her head and hissing at anyone who approached; this behavior demonstrated that Cuban iguanas guard their nest sites. The hatchlings spend several days to two weeks in the nest chamber from the time they hatch to the time they emerge from the nests; dispersing individually after emergence.
Although Cuban iguanas typically remain still for long periods of time and have a slow lumbering gait due to their body mass, they are capable of quick bursts of speed for short distances. Younger animals are more arboreal and will seek refuge in trees, which they can climb with great agility. The animal is a capable swimmer and will take to nearby water if threatened. When cornered they can bite and lash their tails in defense.
at Guantánamo Bay has been estimated at 2,000 to 3,000 individuals, and the animals are treated well and protected by US forces stationed at the base. An unusual incident occurred when a detainee in the prison assaulted a guard with a bloody tail torn from a Cuban iguana in May 2005.
The subspecies, Cyclura nubila caymanensis, is endemic to the "Sister Islands" of Little Cayman
and Cayman Brac
. The population on Cayman Brac is less than 50 of these animals and Little Cayman supports 1,500. A feral population of C. n. caymanensis has been established on Grand Cayman
.
The Cuban iguana makes its burrow near cacti or thistles, sometimes even within the cactus itself. These thorny plants offer protection and their fruit and flowers offer the iguanas food. In areas without cacti, the lizards make their burrows in dead trees, hollow logs, and limestone crevices.
In the mid-1960s a small group of Cuban iguanas was released from a zoo on Isla Magueyes
, southwest of Puerto Rico
, forming an independent free-ranging feral population. As of 2000, there has been talk of removing or relocating this population of iguanas by the US Department of Interior. This feral population is the source for 90% of the captive Cuban iguanas held in private collections and was the source for part of a study on animal communication and evolution conducted by Emilia Martins, a biologist at Indiana University
.
Martins' study compared the head-bob displays from the source population on Cuba with these animals on Isla Magueyes. The durations and pauses were longer by as much as 350% in the feral population. In comparison, the blue iguana of Grand Cayman's head-bob displays differed from those of the animals on Cuba by only about 20%. The rapid change in display structure between the colony of animals on Isla Magueyes and those on Cuba illustrated the potential of small founding population size as a catalyst to evolution with regard to communication
or display. In this case the difference was by only six generations at most.
The Cuban iguana is well-established in public and private collections. Many zoological parks and private individuals keep them in captive breeding program
s, minimizing the demand for wild-caught specimens for the pet trade
. Cuban iguanas are listed as "vulnerable" on the IUCN Red List
. The total population in Cuba is estimated at between 40,000 and 60,000 individuals, and the feral population on Isla Magueyes is estimated at over 1,000. According to Allison Alberts, Chief Conservation Officer of the San Diego Zoo
and lead researcher in Cuba, among the many wildlife species at GTMO, "The Cuban Iguana is one of the largest, undoubtedly the most visible, and certainly the most charismatic. It seems that no one completes a tour of duty at GTMO without getting to know these prehistoric-looking giants."
In a round-about way, the Cuban iguana's status under the US Endangered Species Act
made its way into US jurisprudence. In the fall of 2003, attorney
Tom Wilner needed to persuade the justices of the US Supreme Court to take the case of a dozen Kuwait
i detainees being held in isolation in Guantanamo Bay, Cuba, without charges, without a hearing and without access to a lawyer. According to Peter Honigsberg, a professor of law at the University of San Francisco, Wilner unsuccessfully made two arguments before the Court to hear his case; in his third argument he changed tactics by mentioning US law and the Cuban iguana. Wilner argued, "Anyone, including a federal official, who violates the Endangered Species Act
by harming an iguana at Guantanamo, can be fined and prosecuted. Yet the government argues that US law does not apply to protect the human prisoners there". According to Honigsberg, the Supreme Court agreed to hear the case because of this argument.
, the Hicacos Peninsula
, or Cayo Largo, areas where it was found in great numbers some 30 to 40 years ago.
As opposed to other West Indian islands where iguanids are found, consumption of iguana meat is not widespread in Cuba. Certain fishing communities do practice it for subsistence, but for the most part the animal is not eaten by Cubans. According to naturalist Thomas Barbour
, this is based on unfounded superstitious beliefs which suggest that the iguanas emit a dark fluid reminiscent of the black vomit of yellow fever
victims when they are killed. One of the reasons for their decline is habitat destruction
caused by the overgrazing of farm animals, housing development, and the building of tourist resorts on the beaches where the animals prefer to build their nests. Populations of iguanas suffer by the direct predation of introduced
animals such as rats, cats, and dogs. Feral hogs are responsible for destroying many iguana nest sites which they dig up for eggs. Ant predation of iguana eggs is another threat to the species.
In 1993 the San Diego Zoo
experimentally tested the utility of a "head-starting" program for newly hatched Cuban iguanas with funding from the National Science Foundation's Conservation and Restoration Biology Program. "Head-starting" is a process by which the Cuban iguana's eggs are hatched in an incubator and the animals are protected and fed for the first 20 months of their lives. The purpose is to get the animals to a size where they are more capable of fleeing from or fighting off predators. This technique was originally used to protect hatchling sea turtles, Galapagos land iguana
s, and Ctenosaura bakeri on the island of Utila
, but Alberts used it for the first time on a Cyclura species with the Cuban iguana. The purpose was not only to help the Cuban iguana population, but to test the overall effectiveness of headstarting as a conservation strategy for more critically endangered species of Cyclura.
The strategy proved successful, according to Alberts, when the released head-started iguanas reacted to predators, foraged for food, and behaved like their wild-born counterparts. This strategy has been implemented with great success with other critically endangered species of Cyclura and Ctenosaura
throughout the West Indies and Central America
, notably the Jamaican iguana, Grand Cayman blue iguana, Ricord's iguana
, Allen Cays iguana
, San Salvador iguana, and Anegada iguana
.
of the iguana
family. It is the largest of the West Indian rock iguanas
(genus Cyclura), one of the most endangered groups of lizards. This herbivorous
species with red eyes, a thick tail, and spiked jowls is one of the largest lizards in the Caribbean
.
The Cuban iguana is distributed throughout the rocky southern coastal areas of mainland Cuba
and its surrounding islets with a feral
population thriving on Isla Magueyes, Puerto Rico
. It is also found on the Cayman Islands
of Little Cayman
and Cayman Brac
, where a separate subspecies
occurs. Females guard their nest sites and often nest in sites excavated by Cuban crocodile
s. As a defense measure, the Cuban iguana often makes its home within or near prickly-pear cacti.
Although the wild population is in decline because of predation
by feral
animals and habitat loss caused by human agricultural development, the numbers of iguanas have been bolstered as a result of captive-breeding and other conservation programs. Cyclura nubila has been used to study evolution and animal communication
, and its captive-breeding program has been a model for other endangered lizards in the Caribbean.
The Cuban rock iguana's generic
name Cyclura
is derived from the Ancient Greek
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. John Edward Gray
, the British zoologist
who first described the species in 1831 as Iguana (Cyclura) nubila or "Clouded Guana", gave it the specific name nubila, Latin
for "cloudy".
The closest relatives of Cyclura nubila are the Grand Cayman blue iguana
(Cyclura lewisi) and the Northern Bahamian rock iguana (Cyclura cychlura); phylogenetic analysis indicates that these three species diverged from a common ancestor three million years ago.
Cyclura nubila was previously considered to have three subspecies
, the Grand Cayman blue iguana (termed Cyclura nubila lewisi), the Lesser Caymans iguana (Cyclura nubila caymanensis
), and the nominate Cuban subspecies (Cyclura nubila nubila). This classification was revised after later mitochondrial DNA
analysis and research into the scalation patterns on the heads of Caribbean iguanid lizards (these patterns are unique by species and act as a "fingerprint" of sorts). The Grand Cayman blue iguana is now recognized as a separate species.a
The Cuban iguana is a large lizard, with an average body length of 40 centimetres (15.7 in) from snout to vent (the base of the tail). On rare occasions, individual males with lengths of 1.6 metres (5.2 ft) when measured from the snout to the tip of the tail have been recorded at the wildlife sanctuary within the Guantanamo Bay Naval Base
(GTMO), Cuba with females being two thirds that size. The species is sexually dimorphic
: males are much larger than females, and males have enlarged femoral pore
s on their thighs, which are used to release pheromone
s to attract mates and mark territory. The skin of male Cuban iguanas ranges in color from dark gray to brick red, whereas that of females is olive green with dark stripes or bands. In both sexes, limbs are black with pale brown oval spots and solid black feet. Young animals tend to be dark brown or green with faint darker striping or mottling in five to ten diagonal transverse bands on the body. These bands blend in with the body color as the iguana ages. Both sexes possess a dewlap
(skin hanging below the neck) and a row of spines
running down their back to their thick tail. Their heads and necks are short and stout, their teeth are solid and broad, and they have powerful jaw muscles. Their jowls, which grow larger as the animal ages, are covered in spiky protuberances called tubercles.
The Cuban iguana's eyes have a golden iris
and red sclera
. Cuban iguanas have excellent vision and the ability to detect shapes and movement at long distances. Sensory cells called "double cone
s" give them sharp color vision
and enable them to see ultraviolet
wavelengths. By seeking out locations with more ultraviolet sunlight to bask in, the Cuban iguana optimizes vitamin D
production. Cuban iguanas have poor low-light vision, because they have few rods
or photoreceptor cells. Like other iguanids, Cuban iguanas have a white photosensory organ on the top of their heads, called the parietal eye
. This "eye" has only a rudimentary retina and lens and cannot form images, but it is sensitive to changes in light and can detect movement.
), black mangrove (Avicennia germinans
), red mangrove (Rhizophora mangle
), olives, and various grasses. Aiding in the digestion of this high-cellulose
diet, colonies of nematode
s occupy 50% of the contents of Cuban iguanas' large intestine
s. Cuban iguanas occasionally consume animal matter, and individuals have been observed scavenging the corpses of birds, fish and crabs. Researchers on Isla Magueyes observed a single episode of cannibalism
in 2006 when an adult female iguana chased, caught, and ate a hatchling. The researchers wrote that the dense population on Isla Magueyes could have caused this incident.
Like other herbivorous lizards, the Cuban iguana is presented with a problem for osmoregulation
: plant matter contains more potassium
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike those of mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead, reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
. In the case of the Cuban iguana, which consumes large amounts of vegetation, these excess salt ions are excreted through the salt gland
in the same manner as in birds.
Mating occurs in May and June, and females lay single clutches of three to 30 eggs in June or July. According to field research, females deposit their eggs at the same nesting sites each year. The nests are built near each other as suitable nesting sites are becoming rare. On Cuba's Isla de Juventud, Cuban iguanas nest in pockets of earth exposed to the sun by Cuban crocodiles, after the crocodiles' eggs have hatched. These nests are separate from where adult iguanas live. In areas without crocodiles, the iguanas excavate nests in sandy beaches. At the San Diego Zoo, a female built a nest at the end of a long chamber she excavated in the sand. She stood near it for weeks, defending it by shaking her head and hissing at anyone who approached; this behavior demonstrated that Cuban iguanas guard their nest sites. The hatchlings spend several days to two weeks in the nest chamber from the time they hatch to the time they emerge from the nests; dispersing individually after emergence.
Although Cuban iguanas typically remain still for long periods of time and have a slow lumbering gait due to their body mass, they are capable of quick bursts of speed for short distances. Younger animals are more arboreal and will seek refuge in trees, which they can climb with great agility. The animal is a capable swimmer and will take to nearby water if threatened. When cornered they can bite and lash their tails in defense.
at Guantánamo Bay has been estimated at 2,000 to 3,000 individuals, and the animals are treated well and protected by US forces stationed at the base. An unusual incident occurred when a detainee in the prison assaulted a guard with a bloody tail torn from a Cuban iguana in May 2005.
The subspecies, Cyclura nubila caymanensis, is endemic to the "Sister Islands" of Little Cayman
and Cayman Brac
. The population on Cayman Brac is less than 50 of these animals and Little Cayman supports 1,500. A feral population of C. n. caymanensis has been established on Grand Cayman
.
The Cuban iguana makes its burrow near cacti or thistles, sometimes even within the cactus itself. These thorny plants offer protection and their fruit and flowers offer the iguanas food. In areas without cacti, the lizards make their burrows in dead trees, hollow logs, and limestone crevices.
In the mid-1960s a small group of Cuban iguanas was released from a zoo on Isla Magueyes
, southwest of Puerto Rico
, forming an independent free-ranging feral population. As of 2000, there has been talk of removing or relocating this population of iguanas by the US Department of Interior. This feral population is the source for 90% of the captive Cuban iguanas held in private collections and was the source for part of a study on animal communication and evolution conducted by Emilia Martins, a biologist at Indiana University
.
Martins' study compared the head-bob displays from the source population on Cuba with these animals on Isla Magueyes. The durations and pauses were longer by as much as 350% in the feral population. In comparison, the blue iguana of Grand Cayman's head-bob displays differed from those of the animals on Cuba by only about 20%. The rapid change in display structure between the colony of animals on Isla Magueyes and those on Cuba illustrated the potential of small founding population size as a catalyst to evolution with regard to communication
or display. In this case the difference was by only six generations at most.
The Cuban iguana is well-established in public and private collections. Many zoological parks and private individuals keep them in captive breeding program
s, minimizing the demand for wild-caught specimens for the pet trade
. Cuban iguanas are listed as "vulnerable" on the IUCN Red List
. The total population in Cuba is estimated at between 40,000 and 60,000 individuals, and the feral population on Isla Magueyes is estimated at over 1,000. According to Allison Alberts, Chief Conservation Officer of the San Diego Zoo
and lead researcher in Cuba, among the many wildlife species at GTMO, "The Cuban Iguana is one of the largest, undoubtedly the most visible, and certainly the most charismatic. It seems that no one completes a tour of duty at GTMO without getting to know these prehistoric-looking giants."
In a round-about way, the Cuban iguana's status under the US Endangered Species Act
made its way into US jurisprudence. In the fall of 2003, attorney
Tom Wilner needed to persuade the justices of the US Supreme Court to take the case of a dozen Kuwait
i detainees being held in isolation in Guantanamo Bay, Cuba, without charges, without a hearing and without access to a lawyer. According to Peter Honigsberg, a professor of law at the University of San Francisco, Wilner unsuccessfully made two arguments before the Court to hear his case; in his third argument he changed tactics by mentioning US law and the Cuban iguana. Wilner argued, "Anyone, including a federal official, who violates the Endangered Species Act
by harming an iguana at Guantanamo, can be fined and prosecuted. Yet the government argues that US law does not apply to protect the human prisoners there". According to Honigsberg, the Supreme Court agreed to hear the case because of this argument.
, the Hicacos Peninsula
, or Cayo Largo, areas where it was found in great numbers some 30 to 40 years ago.
As opposed to other West Indian islands where iguanids are found, consumption of iguana meat is not widespread in Cuba. Certain fishing communities do practice it for subsistence, but for the most part the animal is not eaten by Cubans. According to naturalist Thomas Barbour
, this is based on unfounded superstitious beliefs which suggest that the iguanas emit a dark fluid reminiscent of the black vomit of yellow fever
victims when they are killed. One of the reasons for their decline is habitat destruction
caused by the overgrazing of farm animals, housing development, and the building of tourist resorts on the beaches where the animals prefer to build their nests. Populations of iguanas suffer by the direct predation of introduced
animals such as rats, cats, and dogs. Feral hogs are responsible for destroying many iguana nest sites which they dig up for eggs. Ant predation of iguana eggs is another threat to the species.
In 1993 the San Diego Zoo
experimentally tested the utility of a "head-starting" program for newly hatched Cuban iguanas with funding from the National Science Foundation's Conservation and Restoration Biology Program. "Head-starting" is a process by which the Cuban iguana's eggs are hatched in an incubator and the animals are protected and fed for the first 20 months of their lives. The purpose is to get the animals to a size where they are more capable of fleeing from or fighting off predators. This technique was originally used to protect hatchling sea turtles, Galapagos land iguana
s, and Ctenosaura bakeri on the island of Utila
, but Alberts used it for the first time on a Cyclura species with the Cuban iguana. The purpose was not only to help the Cuban iguana population, but to test the overall effectiveness of headstarting as a conservation strategy for more critically endangered species of Cyclura.
The strategy proved successful, according to Alberts, when the released head-started iguanas reacted to predators, foraged for food, and behaved like their wild-born counterparts. This strategy has been implemented with great success with other critically endangered species of Cyclura and Ctenosaura
throughout the West Indies and Central America
, notably the Jamaican iguana, Grand Cayman blue iguana, Ricord's iguana
, Allen Cays iguana
, San Salvador iguana, and Anegada iguana
.
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
of the iguana
Iguanidae
Iguanidae is a family of lizards, composed of iguanas and related species.-Classification of Iguanidae:Two different classification schemes have been used to define the structure of this family. These are the "traditional" classification and the classification presented by Frost et al. .Frost et...
family. It is the largest of the West Indian rock iguanas
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
(genus Cyclura), one of the most endangered groups of lizards. This herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
species with red eyes, a thick tail, and spiked jowls is one of the largest lizards in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
.
The Cuban iguana is distributed throughout the rocky southern coastal areas of mainland Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and its surrounding islets with a feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
population thriving on Isla Magueyes, Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
. It is also found on the Cayman Islands
Cayman Islands
The Cayman Islands is a British Overseas Territory and overseas territory of the European Union located in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac, and Little Cayman, located south of Cuba and northwest of Jamaica...
of Little Cayman
Little Cayman
Little Cayman is an island that is part of the Cayman Islands. It is located in the Caribbean Sea, about 75 miles northeast of Grand Cayman and five miles west of Cayman Brac. Little Cayman has a permanent population of less than 170 and is about 10 miles long with an average width of 1 mile...
and Cayman Brac
Cayman Brac
Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 90 miles northeast of Grand Cayman and 5 miles east of Little Cayman. It is about 12 miles long, with an average width of 1 mile...
, where a separate subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
occurs. Females guard their nest sites and often nest in sites excavated by Cuban crocodile
Cuban crocodile
The Cuban crocodile is a small species of crocodile found only in Cuba's Zapata Swamp and the Isle of Youth, and highly endangered, though it formerly ranged elsewhere in the Caribbean...
s. As a defense measure, the Cuban iguana often makes its home within or near prickly-pear cacti.
Although the wild population is in decline because of predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
by feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
animals and habitat loss caused by human agricultural development, the numbers of iguanas have been bolstered as a result of captive-breeding and other conservation programs. Cyclura nubila has been used to study evolution and animal communication
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
, and its captive-breeding program has been a model for other endangered lizards in the Caribbean.
Taxonomy
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name Cyclura
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
is derived from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. John Edward Gray
John Edward Gray
John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....
, the British zoologist
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
who first described the species in 1831 as Iguana (Cyclura) nubila or "Clouded Guana", gave it the specific name nubila, Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "cloudy".
The closest relatives of Cyclura nubila are the Grand Cayman blue iguana
Blue Iguana
The Blue Iguana or Grand Cayman Iguana is a critically endangered species of lizard of the genus Cyclura endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban Iguana, it was reclassified as a separate species in 2004 because of genetic differences discovered four...
(Cyclura lewisi) and the Northern Bahamian rock iguana (Cyclura cychlura); phylogenetic analysis indicates that these three species diverged from a common ancestor three million years ago.
Cyclura nubila was previously considered to have three subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, the Grand Cayman blue iguana (termed Cyclura nubila lewisi), the Lesser Caymans iguana (Cyclura nubila caymanensis
Cyclura nubila caymanensis
The Lesser Caymans Iguana or Cayman Brac Iguana or Cayman Island Brown Iguana or Sister Isles Iguana is a critically endangered subspecies of the Cuban Iguana...
), and the nominate Cuban subspecies (Cyclura nubila nubila). This classification was revised after later mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
analysis and research into the scalation patterns on the heads of Caribbean iguanid lizards (these patterns are unique by species and act as a "fingerprint" of sorts). The Grand Cayman blue iguana is now recognized as a separate species.a
Anatomy and morphology
Guantanamo Bay Naval Base
Guantanamo Bay Naval Base is located on of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas...
(GTMO), Cuba with females being two thirds that size. The species is sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
: males are much larger than females, and males have enlarged femoral pore
Femoral pore
Femoral pores are a part of a holocrine secretory gland found on the inside of the thighs of certain lizards and amphisbaenians which releases pheromones to attract mates or mark territory. In certain species only the male has these pores and in other species, both sexes have them, with the males...
s on their thighs, which are used to release pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s to attract mates and mark territory. The skin of male Cuban iguanas ranges in color from dark gray to brick red, whereas that of females is olive green with dark stripes or bands. In both sexes, limbs are black with pale brown oval spots and solid black feet. Young animals tend to be dark brown or green with faint darker striping or mottling in five to ten diagonal transverse bands on the body. These bands blend in with the body color as the iguana ages. Both sexes possess a dewlap
Dewlap
A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double...
(skin hanging below the neck) and a row of spines
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
running down their back to their thick tail. Their heads and necks are short and stout, their teeth are solid and broad, and they have powerful jaw muscles. Their jowls, which grow larger as the animal ages, are covered in spiky protuberances called tubercles.
The Cuban iguana's eyes have a golden iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
and red sclera
Sclera
The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...
. Cuban iguanas have excellent vision and the ability to detect shapes and movement at long distances. Sensory cells called "double cone
Cone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
s" give them sharp color vision
Color vision
Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths of the light they reflect, emit, or transmit...
and enable them to see ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
wavelengths. By seeking out locations with more ultraviolet sunlight to bask in, the Cuban iguana optimizes vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
production. Cuban iguanas have poor low-light vision, because they have few rods
Rod cell
Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...
or photoreceptor cells. Like other iguanids, Cuban iguanas have a white photosensory organ on the top of their heads, called the parietal eye
Parietal eye
A parietal eye, also known as a parietal organ or third-eye or pineal eye, is a part of the epithalamus present in some animal species...
. This "eye" has only a rudimentary retina and lens and cannot form images, but it is sensitive to changes in light and can detect movement.
Diet
Like all Cyclura species, the Cuban iguana is primarily herbivorous; 95% of its diet consists of the leaves, flowers and fruits from as many as 30 plant species, including the seaside rock shrub (Rachicallis americana), thistle, prickly pear (Opuntia strictaOpuntia stricta
Opuntia stricta is a species of cactus from southern North America, Central America, the Caribbean, and northern South America. Common names include Erect Prickly Pear and Nopal Estricto ....
), black mangrove (Avicennia germinans
Avicennia germinans
Avicennia germinans, commonly known as the black mangrove, is a species of flowering plant in the acanthus family, Acanthaceae.A. germinans grows in tropical and subtropical regions of the Americas, on both Atlantic and Pacific coasts, and on the Atlantic coast of tropical Africa, where it thrives...
), red mangrove (Rhizophora mangle
Rhizophora mangle
Rhizophora mangle, known as the red mangrove, is distributed in estuarine ecosystems throughout the tropics. Its viviparous "seeds," in actuality called propagules, become fully mature plants before dropping off the parent tree...
), olives, and various grasses. Aiding in the digestion of this high-cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
diet, colonies of nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s occupy 50% of the contents of Cuban iguanas' large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
s. Cuban iguanas occasionally consume animal matter, and individuals have been observed scavenging the corpses of birds, fish and crabs. Researchers on Isla Magueyes observed a single episode of cannibalism
Cannibalism
Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...
in 2006 when an adult female iguana chased, caught, and ate a hatchling. The researchers wrote that the dense population on Isla Magueyes could have caused this incident.
Like other herbivorous lizards, the Cuban iguana is presented with a problem for osmoregulation
Osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move...
: plant matter contains more potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike those of mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead, reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
Cloaca
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
. In the case of the Cuban iguana, which consumes large amounts of vegetation, these excess salt ions are excreted through the salt gland
Salt gland
The salt gland is an organ for excreting excess salts. It is found in elasmobranchs, seabirds, and some reptiles. In sharks, salt glands are found in the rectum, but in birds and reptiles, they are found in or on the skull, in the area of the eyes, nostrils or mouth. In crocodiles, the salt is...
in the same manner as in birds.
Mating and behavior
Cuban iguanas reach sexual maturity at an age of two to three years. Males are gregarious when immature, but become more aggressive as they age, vigorously defending territories in competition for females. Females are more tolerant of each other, except after laying their eggs.Mating occurs in May and June, and females lay single clutches of three to 30 eggs in June or July. According to field research, females deposit their eggs at the same nesting sites each year. The nests are built near each other as suitable nesting sites are becoming rare. On Cuba's Isla de Juventud, Cuban iguanas nest in pockets of earth exposed to the sun by Cuban crocodiles, after the crocodiles' eggs have hatched. These nests are separate from where adult iguanas live. In areas without crocodiles, the iguanas excavate nests in sandy beaches. At the San Diego Zoo, a female built a nest at the end of a long chamber she excavated in the sand. She stood near it for weeks, defending it by shaking her head and hissing at anyone who approached; this behavior demonstrated that Cuban iguanas guard their nest sites. The hatchlings spend several days to two weeks in the nest chamber from the time they hatch to the time they emerge from the nests; dispersing individually after emergence.
Although Cuban iguanas typically remain still for long periods of time and have a slow lumbering gait due to their body mass, they are capable of quick bursts of speed for short distances. Younger animals are more arboreal and will seek refuge in trees, which they can climb with great agility. The animal is a capable swimmer and will take to nearby water if threatened. When cornered they can bite and lash their tails in defense.
Distribution and habitat
The Cuban iguana is naturally distributed in rocky coastal areas on Cuba and throughout as many as 4,000 islets surrounding the Cuban mainland, including Isla de la Juventud off the southern coast, which has one of the most robust populations. Relatively safe populations are found on some islets along the north and south coasts and in isolated protected areas on the mainland. These include Guanahacabibes Biosphere Reserve in the west, Desembarco del Granma National Park, Hatibonico Wildlife Refuge, Punta Negra-Quemados Ecological Reserve, and Delta del Cauto Wildlife Refuge, all in eastern Cuba. Because of this wide distribution, accurate information about the number of distinct subpopulations of Cuban iguanas cannot be determined. The population on the US Naval BaseGuantanamo Bay Naval Base
Guantanamo Bay Naval Base is located on of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas...
at Guantánamo Bay has been estimated at 2,000 to 3,000 individuals, and the animals are treated well and protected by US forces stationed at the base. An unusual incident occurred when a detainee in the prison assaulted a guard with a bloody tail torn from a Cuban iguana in May 2005.
The subspecies, Cyclura nubila caymanensis, is endemic to the "Sister Islands" of Little Cayman
Little Cayman
Little Cayman is an island that is part of the Cayman Islands. It is located in the Caribbean Sea, about 75 miles northeast of Grand Cayman and five miles west of Cayman Brac. Little Cayman has a permanent population of less than 170 and is about 10 miles long with an average width of 1 mile...
and Cayman Brac
Cayman Brac
Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 90 miles northeast of Grand Cayman and 5 miles east of Little Cayman. It is about 12 miles long, with an average width of 1 mile...
. The population on Cayman Brac is less than 50 of these animals and Little Cayman supports 1,500. A feral population of C. n. caymanensis has been established on Grand Cayman
Grand Cayman
Grand Cayman is the largest of the three Cayman Islands and the location of the nation's capital, George Town. In relation to the other two Cayman Islands, it is approximately 75 miles southwest of Little Cayman and 90 miles southwest of Cayman Brac.-Geography:Grand Cayman encompasses 76% of...
.
The Cuban iguana makes its burrow near cacti or thistles, sometimes even within the cactus itself. These thorny plants offer protection and their fruit and flowers offer the iguanas food. In areas without cacti, the lizards make their burrows in dead trees, hollow logs, and limestone crevices.
In the mid-1960s a small group of Cuban iguanas was released from a zoo on Isla Magueyes
Isla Magueyes
Isla Magüeyes is a island from the southwest coast of the island of Puerto Rico. It is encircled with mangrove and has an interior of dry scrub habitat, where it gets its name. It is named for the presence of many century plants or maguey . The surrounding shelf of the island is mostly coral reef...
, southwest of Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, forming an independent free-ranging feral population. As of 2000, there has been talk of removing or relocating this population of iguanas by the US Department of Interior. This feral population is the source for 90% of the captive Cuban iguanas held in private collections and was the source for part of a study on animal communication and evolution conducted by Emilia Martins, a biologist at Indiana University
Indiana University
Indiana University is a multi-campus public university system in the state of Indiana, United States. Indiana University has a combined student body of more than 100,000 students, including approximately 42,000 students enrolled at the Indiana University Bloomington campus and approximately 37,000...
.
Martins' study compared the head-bob displays from the source population on Cuba with these animals on Isla Magueyes. The durations and pauses were longer by as much as 350% in the feral population. In comparison, the blue iguana of Grand Cayman's head-bob displays differed from those of the animals on Cuba by only about 20%. The rapid change in display structure between the colony of animals on Isla Magueyes and those on Cuba illustrated the potential of small founding population size as a catalyst to evolution with regard to communication
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
or display. In this case the difference was by only six generations at most.
Conservation
Breeding program
Breeding programs help animals to breed and can be good for animals as well as the agricultural economy.A breeding program is the planned breeding of a group of animals or plants, usually involving at least several individuals and extending over several generations...
s, minimizing the demand for wild-caught specimens for the pet trade
Wildlife trade
The international wildlife trade is a serious conservation problem, addressed by the United Nations' Convention of International Trade in Endangered Species of Wild Fauna and Flora CITES, which currently has 175 member countries called Parties. The 15th meeting of the Parties took place in Doha,...
. Cuban iguanas are listed as "vulnerable" on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. The total population in Cuba is estimated at between 40,000 and 60,000 individuals, and the feral population on Isla Magueyes is estimated at over 1,000. According to Allison Alberts, Chief Conservation Officer of the San Diego Zoo
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
and lead researcher in Cuba, among the many wildlife species at GTMO, "The Cuban Iguana is one of the largest, undoubtedly the most visible, and certainly the most charismatic. It seems that no one completes a tour of duty at GTMO without getting to know these prehistoric-looking giants."
In a round-about way, the Cuban iguana's status under the US Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
made its way into US jurisprudence. In the fall of 2003, attorney
Guantanamo Bay attorneys
The Center for Constitutional Rights has coordinated efforts by American lawyers to handle the habeas corpus, and other legal appeals, of several hundred of the Guantanamo detainees....
Tom Wilner needed to persuade the justices of the US Supreme Court to take the case of a dozen Kuwait
Kuwait
The State of Kuwait is a sovereign Arab state situated in the north-east of the Arabian Peninsula in Western Asia. It is bordered by Saudi Arabia to the south at Khafji, and Iraq to the north at Basra. It lies on the north-western shore of the Persian Gulf. The name Kuwait is derived from the...
i detainees being held in isolation in Guantanamo Bay, Cuba, without charges, without a hearing and without access to a lawyer. According to Peter Honigsberg, a professor of law at the University of San Francisco, Wilner unsuccessfully made two arguments before the Court to hear his case; in his third argument he changed tactics by mentioning US law and the Cuban iguana. Wilner argued, "Anyone, including a federal official, who violates the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
by harming an iguana at Guantanamo, can be fined and prosecuted. Yet the government argues that US law does not apply to protect the human prisoners there". According to Honigsberg, the Supreme Court agreed to hear the case because of this argument.
Decline
In general the species is in decline, more quickly on the mainland than on the outlying islets. The Cuban mainland populations have been declining at a rate of over 1% per year for the last 10 years. The Cuban iguana is no longer found on the northeastern coast of HavanaHavana
Havana is the capital city, province, major port, and leading commercial centre of Cuba. The city proper has a population of 2.1 million inhabitants, and it spans a total of — making it the largest city in the Caribbean region, and the most populous...
, the Hicacos Peninsula
Hicacos Peninsula
Hicacos is a peninsula on Cuba's northern shore, in the province of Matanzas. The resort town of Varadero is located on the peninsula. The name comes from a species of cactus.-Geography:...
, or Cayo Largo, areas where it was found in great numbers some 30 to 40 years ago.
As opposed to other West Indian islands where iguanids are found, consumption of iguana meat is not widespread in Cuba. Certain fishing communities do practice it for subsistence, but for the most part the animal is not eaten by Cubans. According to naturalist Thomas Barbour
Thomas Barbour
Thomas Barbour was an American herpetologist. From 1927 until 1946, he was director of the Museum of Comparative Zoology founded in 1859 by Louis Agassiz at Harvard University in Cambridge, Massachusetts....
, this is based on unfounded superstitious beliefs which suggest that the iguanas emit a dark fluid reminiscent of the black vomit of yellow fever
Yellow fever
Yellow fever is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family....
victims when they are killed. One of the reasons for their decline is habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
caused by the overgrazing of farm animals, housing development, and the building of tourist resorts on the beaches where the animals prefer to build their nests. Populations of iguanas suffer by the direct predation of introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
animals such as rats, cats, and dogs. Feral hogs are responsible for destroying many iguana nest sites which they dig up for eggs. Ant predation of iguana eggs is another threat to the species.
Recovery
All but one of the major iguana concentrations are either partially or fully protected by the Cuban government. Although no captive-breeding program exists within Cuba, the Centro Nacional de Areas Protegidas (the National Center for Protected Areas) has suggested it will explore this route in the future. In 1985 the Cuban government issued a commemorative peso depicting a Cuban iguana on the head side of the coin in an attempt to raise awareness for this animal.In 1993 the San Diego Zoo
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
experimentally tested the utility of a "head-starting" program for newly hatched Cuban iguanas with funding from the National Science Foundation's Conservation and Restoration Biology Program. "Head-starting" is a process by which the Cuban iguana's eggs are hatched in an incubator and the animals are protected and fed for the first 20 months of their lives. The purpose is to get the animals to a size where they are more capable of fleeing from or fighting off predators. This technique was originally used to protect hatchling sea turtles, Galapagos land iguana
Galapagos Land Iguana
The Galapagos Land Iguana is a species of lizard in the Iguanidae family. It is one of three species of the genus Conolophus...
s, and Ctenosaura bakeri on the island of Utila
Útila
Utila is the third largest of Honduras' Bay Islands, after Roatán and Guanaja, in a region that marks the south end of the Mesoamerican Barrier Reef System, the second-largest in the world...
, but Alberts used it for the first time on a Cyclura species with the Cuban iguana. The purpose was not only to help the Cuban iguana population, but to test the overall effectiveness of headstarting as a conservation strategy for more critically endangered species of Cyclura.
The strategy proved successful, according to Alberts, when the released head-started iguanas reacted to predators, foraged for food, and behaved like their wild-born counterparts. This strategy has been implemented with great success with other critically endangered species of Cyclura and Ctenosaura
Ctenosaura
Ctenosaura is a genus of lizard commonly known as spinytail iguanas. The genus is part of the large lizard family, Iguanidae and is native to Mexico and Central America. The species range in size from about 5 inches to well over one meter. The distinctive feature of this genus is presence of the...
throughout the West Indies and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, notably the Jamaican iguana, Grand Cayman blue iguana, Ricord's iguana
Cyclura ricordi
The Hispaniolan Ground Iguana, Ricord's Ground Iguana, Ricord's Rock Iguana, or Ricord's Iguana is a critically endangered species of rock iguana....
, Allen Cays iguana
Cyclura cychlura inornata
The Allen Cays Rock Iguana is an endangered subspecies of the Northern Bahamian Rock Iguana that is found on Allen Cay in the Bahamas...
, San Salvador iguana, and Anegada iguana
Cyclura pinguis
The Stout Iguana or Anegada Ground Iguana is a critically endangered species of lizard of the genus Cyclura belonging to the Iguanidae family. The species can be found exclusively in the island of Anegada...
.
Footnotes
Cyclura nubila, also known as the Cuban rock iguana, Cuban ground iguana, or Cuban iguana, is a species of lizardLizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
of the iguana
Iguanidae
Iguanidae is a family of lizards, composed of iguanas and related species.-Classification of Iguanidae:Two different classification schemes have been used to define the structure of this family. These are the "traditional" classification and the classification presented by Frost et al. .Frost et...
family. It is the largest of the West Indian rock iguanas
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
(genus Cyclura), one of the most endangered groups of lizards. This herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
species with red eyes, a thick tail, and spiked jowls is one of the largest lizards in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
.
The Cuban iguana is distributed throughout the rocky southern coastal areas of mainland Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and its surrounding islets with a feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
population thriving on Isla Magueyes, Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
. It is also found on the Cayman Islands
Cayman Islands
The Cayman Islands is a British Overseas Territory and overseas territory of the European Union located in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac, and Little Cayman, located south of Cuba and northwest of Jamaica...
of Little Cayman
Little Cayman
Little Cayman is an island that is part of the Cayman Islands. It is located in the Caribbean Sea, about 75 miles northeast of Grand Cayman and five miles west of Cayman Brac. Little Cayman has a permanent population of less than 170 and is about 10 miles long with an average width of 1 mile...
and Cayman Brac
Cayman Brac
Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 90 miles northeast of Grand Cayman and 5 miles east of Little Cayman. It is about 12 miles long, with an average width of 1 mile...
, where a separate subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
occurs. Females guard their nest sites and often nest in sites excavated by Cuban crocodile
Cuban crocodile
The Cuban crocodile is a small species of crocodile found only in Cuba's Zapata Swamp and the Isle of Youth, and highly endangered, though it formerly ranged elsewhere in the Caribbean...
s. As a defense measure, the Cuban iguana often makes its home within or near prickly-pear cacti.
Although the wild population is in decline because of predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
by feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
animals and habitat loss caused by human agricultural development, the numbers of iguanas have been bolstered as a result of captive-breeding and other conservation programs. Cyclura nubila has been used to study evolution and animal communication
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
, and its captive-breeding program has been a model for other endangered lizards in the Caribbean.
Taxonomy
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name Cyclura
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
is derived from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. John Edward Gray
John Edward Gray
John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....
, the British zoologist
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
who first described the species in 1831 as Iguana (Cyclura) nubila or "Clouded Guana", gave it the specific name nubila, Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "cloudy".
The closest relatives of Cyclura nubila are the Grand Cayman blue iguana
Blue Iguana
The Blue Iguana or Grand Cayman Iguana is a critically endangered species of lizard of the genus Cyclura endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban Iguana, it was reclassified as a separate species in 2004 because of genetic differences discovered four...
(Cyclura lewisi) and the Northern Bahamian rock iguana (Cyclura cychlura); phylogenetic analysis indicates that these three species diverged from a common ancestor three million years ago.
Cyclura nubila was previously considered to have three subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, the Grand Cayman blue iguana (termed Cyclura nubila lewisi), the Lesser Caymans iguana (Cyclura nubila caymanensis
Cyclura nubila caymanensis
The Lesser Caymans Iguana or Cayman Brac Iguana or Cayman Island Brown Iguana or Sister Isles Iguana is a critically endangered subspecies of the Cuban Iguana...
), and the nominate Cuban subspecies (Cyclura nubila nubila). This classification was revised after later mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
analysis and research into the scalation patterns on the heads of Caribbean iguanid lizards (these patterns are unique by species and act as a "fingerprint" of sorts). The Grand Cayman blue iguana is now recognized as a separate species.a
Anatomy and morphology
Guantanamo Bay Naval Base
Guantanamo Bay Naval Base is located on of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas...
(GTMO), Cuba with females being two thirds that size. The species is sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
: males are much larger than females, and males have enlarged femoral pore
Femoral pore
Femoral pores are a part of a holocrine secretory gland found on the inside of the thighs of certain lizards and amphisbaenians which releases pheromones to attract mates or mark territory. In certain species only the male has these pores and in other species, both sexes have them, with the males...
s on their thighs, which are used to release pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s to attract mates and mark territory. The skin of male Cuban iguanas ranges in color from dark gray to brick red, whereas that of females is olive green with dark stripes or bands. In both sexes, limbs are black with pale brown oval spots and solid black feet. Young animals tend to be dark brown or green with faint darker striping or mottling in five to ten diagonal transverse bands on the body. These bands blend in with the body color as the iguana ages. Both sexes possess a dewlap
Dewlap
A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double...
(skin hanging below the neck) and a row of spines
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
running down their back to their thick tail. Their heads and necks are short and stout, their teeth are solid and broad, and they have powerful jaw muscles. Their jowls, which grow larger as the animal ages, are covered in spiky protuberances called tubercles.
The Cuban iguana's eyes have a golden iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
and red sclera
Sclera
The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...
. Cuban iguanas have excellent vision and the ability to detect shapes and movement at long distances. Sensory cells called "double cone
Cone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
s" give them sharp color vision
Color vision
Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths of the light they reflect, emit, or transmit...
and enable them to see ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
wavelengths. By seeking out locations with more ultraviolet sunlight to bask in, the Cuban iguana optimizes vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
production. Cuban iguanas have poor low-light vision, because they have few rods
Rod cell
Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...
or photoreceptor cells. Like other iguanids, Cuban iguanas have a white photosensory organ on the top of their heads, called the parietal eye
Parietal eye
A parietal eye, also known as a parietal organ or third-eye or pineal eye, is a part of the epithalamus present in some animal species...
. This "eye" has only a rudimentary retina and lens and cannot form images, but it is sensitive to changes in light and can detect movement.
Diet
Like all Cyclura species, the Cuban iguana is primarily herbivorous; 95% of its diet consists of the leaves, flowers and fruits from as many as 30 plant species, including the seaside rock shrub (Rachicallis americana), thistle, prickly pear (Opuntia strictaOpuntia stricta
Opuntia stricta is a species of cactus from southern North America, Central America, the Caribbean, and northern South America. Common names include Erect Prickly Pear and Nopal Estricto ....
), black mangrove (Avicennia germinans
Avicennia germinans
Avicennia germinans, commonly known as the black mangrove, is a species of flowering plant in the acanthus family, Acanthaceae.A. germinans grows in tropical and subtropical regions of the Americas, on both Atlantic and Pacific coasts, and on the Atlantic coast of tropical Africa, where it thrives...
), red mangrove (Rhizophora mangle
Rhizophora mangle
Rhizophora mangle, known as the red mangrove, is distributed in estuarine ecosystems throughout the tropics. Its viviparous "seeds," in actuality called propagules, become fully mature plants before dropping off the parent tree...
), olives, and various grasses. Aiding in the digestion of this high-cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
diet, colonies of nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s occupy 50% of the contents of Cuban iguanas' large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
s. Cuban iguanas occasionally consume animal matter, and individuals have been observed scavenging the corpses of birds, fish and crabs. Researchers on Isla Magueyes observed a single episode of cannibalism
Cannibalism
Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...
in 2006 when an adult female iguana chased, caught, and ate a hatchling. The researchers wrote that the dense population on Isla Magueyes could have caused this incident.
Like other herbivorous lizards, the Cuban iguana is presented with a problem for osmoregulation
Osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move...
: plant matter contains more potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike those of mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead, reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
Cloaca
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
. In the case of the Cuban iguana, which consumes large amounts of vegetation, these excess salt ions are excreted through the salt gland
Salt gland
The salt gland is an organ for excreting excess salts. It is found in elasmobranchs, seabirds, and some reptiles. In sharks, salt glands are found in the rectum, but in birds and reptiles, they are found in or on the skull, in the area of the eyes, nostrils or mouth. In crocodiles, the salt is...
in the same manner as in birds.
Mating and behavior
Cuban iguanas reach sexual maturity at an age of two to three years. Males are gregarious when immature, but become more aggressive as they age, vigorously defending territories in competition for females. Females are more tolerant of each other, except after laying their eggs.Mating occurs in May and June, and females lay single clutches of three to 30 eggs in June or July. According to field research, females deposit their eggs at the same nesting sites each year. The nests are built near each other as suitable nesting sites are becoming rare. On Cuba's Isla de Juventud, Cuban iguanas nest in pockets of earth exposed to the sun by Cuban crocodiles, after the crocodiles' eggs have hatched. These nests are separate from where adult iguanas live. In areas without crocodiles, the iguanas excavate nests in sandy beaches. At the San Diego Zoo, a female built a nest at the end of a long chamber she excavated in the sand. She stood near it for weeks, defending it by shaking her head and hissing at anyone who approached; this behavior demonstrated that Cuban iguanas guard their nest sites. The hatchlings spend several days to two weeks in the nest chamber from the time they hatch to the time they emerge from the nests; dispersing individually after emergence.
Although Cuban iguanas typically remain still for long periods of time and have a slow lumbering gait due to their body mass, they are capable of quick bursts of speed for short distances. Younger animals are more arboreal and will seek refuge in trees, which they can climb with great agility. The animal is a capable swimmer and will take to nearby water if threatened. When cornered they can bite and lash their tails in defense.
Distribution and habitat
The Cuban iguana is naturally distributed in rocky coastal areas on Cuba and throughout as many as 4,000 islets surrounding the Cuban mainland, including Isla de la Juventud off the southern coast, which has one of the most robust populations. Relatively safe populations are found on some islets along the north and south coasts and in isolated protected areas on the mainland. These include Guanahacabibes Biosphere Reserve in the west, Desembarco del Granma National Park, Hatibonico Wildlife Refuge, Punta Negra-Quemados Ecological Reserve, and Delta del Cauto Wildlife Refuge, all in eastern Cuba. Because of this wide distribution, accurate information about the number of distinct subpopulations of Cuban iguanas cannot be determined. The population on the US Naval BaseGuantanamo Bay Naval Base
Guantanamo Bay Naval Base is located on of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas...
at Guantánamo Bay has been estimated at 2,000 to 3,000 individuals, and the animals are treated well and protected by US forces stationed at the base. An unusual incident occurred when a detainee in the prison assaulted a guard with a bloody tail torn from a Cuban iguana in May 2005.
The subspecies, Cyclura nubila caymanensis, is endemic to the "Sister Islands" of Little Cayman
Little Cayman
Little Cayman is an island that is part of the Cayman Islands. It is located in the Caribbean Sea, about 75 miles northeast of Grand Cayman and five miles west of Cayman Brac. Little Cayman has a permanent population of less than 170 and is about 10 miles long with an average width of 1 mile...
and Cayman Brac
Cayman Brac
Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 90 miles northeast of Grand Cayman and 5 miles east of Little Cayman. It is about 12 miles long, with an average width of 1 mile...
. The population on Cayman Brac is less than 50 of these animals and Little Cayman supports 1,500. A feral population of C. n. caymanensis has been established on Grand Cayman
Grand Cayman
Grand Cayman is the largest of the three Cayman Islands and the location of the nation's capital, George Town. In relation to the other two Cayman Islands, it is approximately 75 miles southwest of Little Cayman and 90 miles southwest of Cayman Brac.-Geography:Grand Cayman encompasses 76% of...
.
The Cuban iguana makes its burrow near cacti or thistles, sometimes even within the cactus itself. These thorny plants offer protection and their fruit and flowers offer the iguanas food. In areas without cacti, the lizards make their burrows in dead trees, hollow logs, and limestone crevices.
In the mid-1960s a small group of Cuban iguanas was released from a zoo on Isla Magueyes
Isla Magueyes
Isla Magüeyes is a island from the southwest coast of the island of Puerto Rico. It is encircled with mangrove and has an interior of dry scrub habitat, where it gets its name. It is named for the presence of many century plants or maguey . The surrounding shelf of the island is mostly coral reef...
, southwest of Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, forming an independent free-ranging feral population. As of 2000, there has been talk of removing or relocating this population of iguanas by the US Department of Interior. This feral population is the source for 90% of the captive Cuban iguanas held in private collections and was the source for part of a study on animal communication and evolution conducted by Emilia Martins, a biologist at Indiana University
Indiana University
Indiana University is a multi-campus public university system in the state of Indiana, United States. Indiana University has a combined student body of more than 100,000 students, including approximately 42,000 students enrolled at the Indiana University Bloomington campus and approximately 37,000...
.
Martins' study compared the head-bob displays from the source population on Cuba with these animals on Isla Magueyes. The durations and pauses were longer by as much as 350% in the feral population. In comparison, the blue iguana of Grand Cayman's head-bob displays differed from those of the animals on Cuba by only about 20%. The rapid change in display structure between the colony of animals on Isla Magueyes and those on Cuba illustrated the potential of small founding population size as a catalyst to evolution with regard to communication
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
or display. In this case the difference was by only six generations at most.
Conservation
Breeding program
Breeding programs help animals to breed and can be good for animals as well as the agricultural economy.A breeding program is the planned breeding of a group of animals or plants, usually involving at least several individuals and extending over several generations...
s, minimizing the demand for wild-caught specimens for the pet trade
Wildlife trade
The international wildlife trade is a serious conservation problem, addressed by the United Nations' Convention of International Trade in Endangered Species of Wild Fauna and Flora CITES, which currently has 175 member countries called Parties. The 15th meeting of the Parties took place in Doha,...
. Cuban iguanas are listed as "vulnerable" on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. The total population in Cuba is estimated at between 40,000 and 60,000 individuals, and the feral population on Isla Magueyes is estimated at over 1,000. According to Allison Alberts, Chief Conservation Officer of the San Diego Zoo
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
and lead researcher in Cuba, among the many wildlife species at GTMO, "The Cuban Iguana is one of the largest, undoubtedly the most visible, and certainly the most charismatic. It seems that no one completes a tour of duty at GTMO without getting to know these prehistoric-looking giants."
In a round-about way, the Cuban iguana's status under the US Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
made its way into US jurisprudence. In the fall of 2003, attorney
Guantanamo Bay attorneys
The Center for Constitutional Rights has coordinated efforts by American lawyers to handle the habeas corpus, and other legal appeals, of several hundred of the Guantanamo detainees....
Tom Wilner needed to persuade the justices of the US Supreme Court to take the case of a dozen Kuwait
Kuwait
The State of Kuwait is a sovereign Arab state situated in the north-east of the Arabian Peninsula in Western Asia. It is bordered by Saudi Arabia to the south at Khafji, and Iraq to the north at Basra. It lies on the north-western shore of the Persian Gulf. The name Kuwait is derived from the...
i detainees being held in isolation in Guantanamo Bay, Cuba, without charges, without a hearing and without access to a lawyer. According to Peter Honigsberg, a professor of law at the University of San Francisco, Wilner unsuccessfully made two arguments before the Court to hear his case; in his third argument he changed tactics by mentioning US law and the Cuban iguana. Wilner argued, "Anyone, including a federal official, who violates the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
by harming an iguana at Guantanamo, can be fined and prosecuted. Yet the government argues that US law does not apply to protect the human prisoners there". According to Honigsberg, the Supreme Court agreed to hear the case because of this argument.
Decline
In general the species is in decline, more quickly on the mainland than on the outlying islets. The Cuban mainland populations have been declining at a rate of over 1% per year for the last 10 years. The Cuban iguana is no longer found on the northeastern coast of HavanaHavana
Havana is the capital city, province, major port, and leading commercial centre of Cuba. The city proper has a population of 2.1 million inhabitants, and it spans a total of — making it the largest city in the Caribbean region, and the most populous...
, the Hicacos Peninsula
Hicacos Peninsula
Hicacos is a peninsula on Cuba's northern shore, in the province of Matanzas. The resort town of Varadero is located on the peninsula. The name comes from a species of cactus.-Geography:...
, or Cayo Largo, areas where it was found in great numbers some 30 to 40 years ago.
As opposed to other West Indian islands where iguanids are found, consumption of iguana meat is not widespread in Cuba. Certain fishing communities do practice it for subsistence, but for the most part the animal is not eaten by Cubans. According to naturalist Thomas Barbour
Thomas Barbour
Thomas Barbour was an American herpetologist. From 1927 until 1946, he was director of the Museum of Comparative Zoology founded in 1859 by Louis Agassiz at Harvard University in Cambridge, Massachusetts....
, this is based on unfounded superstitious beliefs which suggest that the iguanas emit a dark fluid reminiscent of the black vomit of yellow fever
Yellow fever
Yellow fever is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family....
victims when they are killed. One of the reasons for their decline is habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
caused by the overgrazing of farm animals, housing development, and the building of tourist resorts on the beaches where the animals prefer to build their nests. Populations of iguanas suffer by the direct predation of introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
animals such as rats, cats, and dogs. Feral hogs are responsible for destroying many iguana nest sites which they dig up for eggs. Ant predation of iguana eggs is another threat to the species.
Recovery
All but one of the major iguana concentrations are either partially or fully protected by the Cuban government. Although no captive-breeding program exists within Cuba, the Centro Nacional de Areas Protegidas (the National Center for Protected Areas) has suggested it will explore this route in the future. In 1985 the Cuban government issued a commemorative peso depicting a Cuban iguana on the head side of the coin in an attempt to raise awareness for this animal.In 1993 the San Diego Zoo
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
experimentally tested the utility of a "head-starting" program for newly hatched Cuban iguanas with funding from the National Science Foundation's Conservation and Restoration Biology Program. "Head-starting" is a process by which the Cuban iguana's eggs are hatched in an incubator and the animals are protected and fed for the first 20 months of their lives. The purpose is to get the animals to a size where they are more capable of fleeing from or fighting off predators. This technique was originally used to protect hatchling sea turtles, Galapagos land iguana
Galapagos Land Iguana
The Galapagos Land Iguana is a species of lizard in the Iguanidae family. It is one of three species of the genus Conolophus...
s, and Ctenosaura bakeri on the island of Utila
Útila
Utila is the third largest of Honduras' Bay Islands, after Roatán and Guanaja, in a region that marks the south end of the Mesoamerican Barrier Reef System, the second-largest in the world...
, but Alberts used it for the first time on a Cyclura species with the Cuban iguana. The purpose was not only to help the Cuban iguana population, but to test the overall effectiveness of headstarting as a conservation strategy for more critically endangered species of Cyclura.
The strategy proved successful, according to Alberts, when the released head-started iguanas reacted to predators, foraged for food, and behaved like their wild-born counterparts. This strategy has been implemented with great success with other critically endangered species of Cyclura and Ctenosaura
Ctenosaura
Ctenosaura is a genus of lizard commonly known as spinytail iguanas. The genus is part of the large lizard family, Iguanidae and is native to Mexico and Central America. The species range in size from about 5 inches to well over one meter. The distinctive feature of this genus is presence of the...
throughout the West Indies and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, notably the Jamaican iguana, Grand Cayman blue iguana, Ricord's iguana
Cyclura ricordi
The Hispaniolan Ground Iguana, Ricord's Ground Iguana, Ricord's Rock Iguana, or Ricord's Iguana is a critically endangered species of rock iguana....
, Allen Cays iguana
Cyclura cychlura inornata
The Allen Cays Rock Iguana is an endangered subspecies of the Northern Bahamian Rock Iguana that is found on Allen Cay in the Bahamas...
, San Salvador iguana, and Anegada iguana
Cyclura pinguis
The Stout Iguana or Anegada Ground Iguana is a critically endangered species of lizard of the genus Cyclura belonging to the Iguanidae family. The species can be found exclusively in the island of Anegada...
.
Footnotes
Cyclura nubila, also known as the Cuban rock iguana, Cuban ground iguana, or Cuban iguana, is a species of lizardLizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
of the iguana
Iguanidae
Iguanidae is a family of lizards, composed of iguanas and related species.-Classification of Iguanidae:Two different classification schemes have been used to define the structure of this family. These are the "traditional" classification and the classification presented by Frost et al. .Frost et...
family. It is the largest of the West Indian rock iguanas
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
(genus Cyclura), one of the most endangered groups of lizards. This herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
species with red eyes, a thick tail, and spiked jowls is one of the largest lizards in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
.
The Cuban iguana is distributed throughout the rocky southern coastal areas of mainland Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and its surrounding islets with a feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
population thriving on Isla Magueyes, Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
. It is also found on the Cayman Islands
Cayman Islands
The Cayman Islands is a British Overseas Territory and overseas territory of the European Union located in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac, and Little Cayman, located south of Cuba and northwest of Jamaica...
of Little Cayman
Little Cayman
Little Cayman is an island that is part of the Cayman Islands. It is located in the Caribbean Sea, about 75 miles northeast of Grand Cayman and five miles west of Cayman Brac. Little Cayman has a permanent population of less than 170 and is about 10 miles long with an average width of 1 mile...
and Cayman Brac
Cayman Brac
Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 90 miles northeast of Grand Cayman and 5 miles east of Little Cayman. It is about 12 miles long, with an average width of 1 mile...
, where a separate subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
occurs. Females guard their nest sites and often nest in sites excavated by Cuban crocodile
Cuban crocodile
The Cuban crocodile is a small species of crocodile found only in Cuba's Zapata Swamp and the Isle of Youth, and highly endangered, though it formerly ranged elsewhere in the Caribbean...
s. As a defense measure, the Cuban iguana often makes its home within or near prickly-pear cacti.
Although the wild population is in decline because of predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
by feral
Feral
A feral organism is one that has changed from being domesticated to being wild or untamed. In the case of plants it is a movement from cultivated to uncultivated or controlled to volunteer. The introduction of feral animals or plants to their non-native regions, like any introduced species, may...
animals and habitat loss caused by human agricultural development, the numbers of iguanas have been bolstered as a result of captive-breeding and other conservation programs. Cyclura nubila has been used to study evolution and animal communication
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
, and its captive-breeding program has been a model for other endangered lizards in the Caribbean.
Taxonomy
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name Cyclura
Cyclura
Cyclura is a genus of lizards from the family Iguanidae. Members of this genus are known as "cyclurids" or more commonly as rock iguanas and only occur on islands in the West Indies...
is derived from the Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
cyclos (κύκλος) meaning "circular" and ourá (οὐρά) meaning "tail", after the thick-ringed tail characteristic of all Cyclura. John Edward Gray
John Edward Gray
John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....
, the British zoologist
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
who first described the species in 1831 as Iguana (Cyclura) nubila or "Clouded Guana", gave it the specific name nubila, Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "cloudy".
The closest relatives of Cyclura nubila are the Grand Cayman blue iguana
Blue Iguana
The Blue Iguana or Grand Cayman Iguana is a critically endangered species of lizard of the genus Cyclura endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban Iguana, it was reclassified as a separate species in 2004 because of genetic differences discovered four...
(Cyclura lewisi) and the Northern Bahamian rock iguana (Cyclura cychlura); phylogenetic analysis indicates that these three species diverged from a common ancestor three million years ago.
Cyclura nubila was previously considered to have three subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, the Grand Cayman blue iguana (termed Cyclura nubila lewisi), the Lesser Caymans iguana (Cyclura nubila caymanensis
Cyclura nubila caymanensis
The Lesser Caymans Iguana or Cayman Brac Iguana or Cayman Island Brown Iguana or Sister Isles Iguana is a critically endangered subspecies of the Cuban Iguana...
), and the nominate Cuban subspecies (Cyclura nubila nubila). This classification was revised after later mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
analysis and research into the scalation patterns on the heads of Caribbean iguanid lizards (these patterns are unique by species and act as a "fingerprint" of sorts). The Grand Cayman blue iguana is now recognized as a separate species.a
Anatomy and morphology
Guantanamo Bay Naval Base
Guantanamo Bay Naval Base is located on of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas...
(GTMO), Cuba with females being two thirds that size. The species is sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
: males are much larger than females, and males have enlarged femoral pore
Femoral pore
Femoral pores are a part of a holocrine secretory gland found on the inside of the thighs of certain lizards and amphisbaenians which releases pheromones to attract mates or mark territory. In certain species only the male has these pores and in other species, both sexes have them, with the males...
s on their thighs, which are used to release pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s to attract mates and mark territory. The skin of male Cuban iguanas ranges in color from dark gray to brick red, whereas that of females is olive green with dark stripes or bands. In both sexes, limbs are black with pale brown oval spots and solid black feet. Young animals tend to be dark brown or green with faint darker striping or mottling in five to ten diagonal transverse bands on the body. These bands blend in with the body color as the iguana ages. Both sexes possess a dewlap
Dewlap
A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double...
(skin hanging below the neck) and a row of spines
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
running down their back to their thick tail. Their heads and necks are short and stout, their teeth are solid and broad, and they have powerful jaw muscles. Their jowls, which grow larger as the animal ages, are covered in spiky protuberances called tubercles.
The Cuban iguana's eyes have a golden iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
and red sclera
Sclera
The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...
. Cuban iguanas have excellent vision and the ability to detect shapes and movement at long distances. Sensory cells called "double cone
Cone cell
Cone cells, or cones, are photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, as opposed to rod cells that work better in dim light. If the retina is exposed to an intense visual stimulus, a negative afterimage will be...
s" give them sharp color vision
Color vision
Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths of the light they reflect, emit, or transmit...
and enable them to see ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
wavelengths. By seeking out locations with more ultraviolet sunlight to bask in, the Cuban iguana optimizes vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
production. Cuban iguanas have poor low-light vision, because they have few rods
Rod cell
Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of visual photoreceptor, cone cells. Named for their cylindrical shape, rods are concentrated at the outer edges of the retina and are used in peripheral vision. On...
or photoreceptor cells. Like other iguanids, Cuban iguanas have a white photosensory organ on the top of their heads, called the parietal eye
Parietal eye
A parietal eye, also known as a parietal organ or third-eye or pineal eye, is a part of the epithalamus present in some animal species...
. This "eye" has only a rudimentary retina and lens and cannot form images, but it is sensitive to changes in light and can detect movement.
Diet
Like all Cyclura species, the Cuban iguana is primarily herbivorous; 95% of its diet consists of the leaves, flowers and fruits from as many as 30 plant species, including the seaside rock shrub (Rachicallis americana), thistle, prickly pear (Opuntia strictaOpuntia stricta
Opuntia stricta is a species of cactus from southern North America, Central America, the Caribbean, and northern South America. Common names include Erect Prickly Pear and Nopal Estricto ....
), black mangrove (Avicennia germinans
Avicennia germinans
Avicennia germinans, commonly known as the black mangrove, is a species of flowering plant in the acanthus family, Acanthaceae.A. germinans grows in tropical and subtropical regions of the Americas, on both Atlantic and Pacific coasts, and on the Atlantic coast of tropical Africa, where it thrives...
), red mangrove (Rhizophora mangle
Rhizophora mangle
Rhizophora mangle, known as the red mangrove, is distributed in estuarine ecosystems throughout the tropics. Its viviparous "seeds," in actuality called propagules, become fully mature plants before dropping off the parent tree...
), olives, and various grasses. Aiding in the digestion of this high-cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
diet, colonies of nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s occupy 50% of the contents of Cuban iguanas' large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
s. Cuban iguanas occasionally consume animal matter, and individuals have been observed scavenging the corpses of birds, fish and crabs. Researchers on Isla Magueyes observed a single episode of cannibalism
Cannibalism
Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...
in 2006 when an adult female iguana chased, caught, and ate a hatchling. The researchers wrote that the dense population on Isla Magueyes could have caused this incident.
Like other herbivorous lizards, the Cuban iguana is presented with a problem for osmoregulation
Osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move...
: plant matter contains more potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
and has less nutritional content per gram than meat so more must be eaten to meet the lizard's metabolic needs. Unlike those of mammals, reptile kidneys cannot concentrate urine to save on water intake. Instead, reptiles excrete toxic nitrogenous wastes as solid uric acid through their cloaca
Cloaca
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary tracts of certain animal species...
. In the case of the Cuban iguana, which consumes large amounts of vegetation, these excess salt ions are excreted through the salt gland
Salt gland
The salt gland is an organ for excreting excess salts. It is found in elasmobranchs, seabirds, and some reptiles. In sharks, salt glands are found in the rectum, but in birds and reptiles, they are found in or on the skull, in the area of the eyes, nostrils or mouth. In crocodiles, the salt is...
in the same manner as in birds.
Mating and behavior
Cuban iguanas reach sexual maturity at an age of two to three years. Males are gregarious when immature, but become more aggressive as they age, vigorously defending territories in competition for females. Females are more tolerant of each other, except after laying their eggs.Mating occurs in May and June, and females lay single clutches of three to 30 eggs in June or July. According to field research, females deposit their eggs at the same nesting sites each year. The nests are built near each other as suitable nesting sites are becoming rare. On Cuba's Isla de Juventud, Cuban iguanas nest in pockets of earth exposed to the sun by Cuban crocodiles, after the crocodiles' eggs have hatched. These nests are separate from where adult iguanas live. In areas without crocodiles, the iguanas excavate nests in sandy beaches. At the San Diego Zoo, a female built a nest at the end of a long chamber she excavated in the sand. She stood near it for weeks, defending it by shaking her head and hissing at anyone who approached; this behavior demonstrated that Cuban iguanas guard their nest sites. The hatchlings spend several days to two weeks in the nest chamber from the time they hatch to the time they emerge from the nests; dispersing individually after emergence.
Although Cuban iguanas typically remain still for long periods of time and have a slow lumbering gait due to their body mass, they are capable of quick bursts of speed for short distances. Younger animals are more arboreal and will seek refuge in trees, which they can climb with great agility. The animal is a capable swimmer and will take to nearby water if threatened. When cornered they can bite and lash their tails in defense.
Distribution and habitat
The Cuban iguana is naturally distributed in rocky coastal areas on Cuba and throughout as many as 4,000 islets surrounding the Cuban mainland, including Isla de la Juventud off the southern coast, which has one of the most robust populations. Relatively safe populations are found on some islets along the north and south coasts and in isolated protected areas on the mainland. These include Guanahacabibes Biosphere Reserve in the west, Desembarco del Granma National Park, Hatibonico Wildlife Refuge, Punta Negra-Quemados Ecological Reserve, and Delta del Cauto Wildlife Refuge, all in eastern Cuba. Because of this wide distribution, accurate information about the number of distinct subpopulations of Cuban iguanas cannot be determined. The population on the US Naval BaseGuantanamo Bay Naval Base
Guantanamo Bay Naval Base is located on of land and water at Guantánamo Bay, Cuba which the United States leased for use as a coaling station following the Cuban-American Treaty of 1903. The base is located on the shore of Guantánamo Bay at the southeastern end of Cuba. It is the oldest overseas...
at Guantánamo Bay has been estimated at 2,000 to 3,000 individuals, and the animals are treated well and protected by US forces stationed at the base. An unusual incident occurred when a detainee in the prison assaulted a guard with a bloody tail torn from a Cuban iguana in May 2005.
The subspecies, Cyclura nubila caymanensis, is endemic to the "Sister Islands" of Little Cayman
Little Cayman
Little Cayman is an island that is part of the Cayman Islands. It is located in the Caribbean Sea, about 75 miles northeast of Grand Cayman and five miles west of Cayman Brac. Little Cayman has a permanent population of less than 170 and is about 10 miles long with an average width of 1 mile...
and Cayman Brac
Cayman Brac
Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 90 miles northeast of Grand Cayman and 5 miles east of Little Cayman. It is about 12 miles long, with an average width of 1 mile...
. The population on Cayman Brac is less than 50 of these animals and Little Cayman supports 1,500. A feral population of C. n. caymanensis has been established on Grand Cayman
Grand Cayman
Grand Cayman is the largest of the three Cayman Islands and the location of the nation's capital, George Town. In relation to the other two Cayman Islands, it is approximately 75 miles southwest of Little Cayman and 90 miles southwest of Cayman Brac.-Geography:Grand Cayman encompasses 76% of...
.
The Cuban iguana makes its burrow near cacti or thistles, sometimes even within the cactus itself. These thorny plants offer protection and their fruit and flowers offer the iguanas food. In areas without cacti, the lizards make their burrows in dead trees, hollow logs, and limestone crevices.
In the mid-1960s a small group of Cuban iguanas was released from a zoo on Isla Magueyes
Isla Magueyes
Isla Magüeyes is a island from the southwest coast of the island of Puerto Rico. It is encircled with mangrove and has an interior of dry scrub habitat, where it gets its name. It is named for the presence of many century plants or maguey . The surrounding shelf of the island is mostly coral reef...
, southwest of Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, forming an independent free-ranging feral population. As of 2000, there has been talk of removing or relocating this population of iguanas by the US Department of Interior. This feral population is the source for 90% of the captive Cuban iguanas held in private collections and was the source for part of a study on animal communication and evolution conducted by Emilia Martins, a biologist at Indiana University
Indiana University
Indiana University is a multi-campus public university system in the state of Indiana, United States. Indiana University has a combined student body of more than 100,000 students, including approximately 42,000 students enrolled at the Indiana University Bloomington campus and approximately 37,000...
.
Martins' study compared the head-bob displays from the source population on Cuba with these animals on Isla Magueyes. The durations and pauses were longer by as much as 350% in the feral population. In comparison, the blue iguana of Grand Cayman's head-bob displays differed from those of the animals on Cuba by only about 20%. The rapid change in display structure between the colony of animals on Isla Magueyes and those on Cuba illustrated the potential of small founding population size as a catalyst to evolution with regard to communication
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
or display. In this case the difference was by only six generations at most.
Conservation
Breeding program
Breeding programs help animals to breed and can be good for animals as well as the agricultural economy.A breeding program is the planned breeding of a group of animals or plants, usually involving at least several individuals and extending over several generations...
s, minimizing the demand for wild-caught specimens for the pet trade
Wildlife trade
The international wildlife trade is a serious conservation problem, addressed by the United Nations' Convention of International Trade in Endangered Species of Wild Fauna and Flora CITES, which currently has 175 member countries called Parties. The 15th meeting of the Parties took place in Doha,...
. Cuban iguanas are listed as "vulnerable" on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. The total population in Cuba is estimated at between 40,000 and 60,000 individuals, and the feral population on Isla Magueyes is estimated at over 1,000. According to Allison Alberts, Chief Conservation Officer of the San Diego Zoo
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
and lead researcher in Cuba, among the many wildlife species at GTMO, "The Cuban Iguana is one of the largest, undoubtedly the most visible, and certainly the most charismatic. It seems that no one completes a tour of duty at GTMO without getting to know these prehistoric-looking giants."
In a round-about way, the Cuban iguana's status under the US Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
made its way into US jurisprudence. In the fall of 2003, attorney
Guantanamo Bay attorneys
The Center for Constitutional Rights has coordinated efforts by American lawyers to handle the habeas corpus, and other legal appeals, of several hundred of the Guantanamo detainees....
Tom Wilner needed to persuade the justices of the US Supreme Court to take the case of a dozen Kuwait
Kuwait
The State of Kuwait is a sovereign Arab state situated in the north-east of the Arabian Peninsula in Western Asia. It is bordered by Saudi Arabia to the south at Khafji, and Iraq to the north at Basra. It lies on the north-western shore of the Persian Gulf. The name Kuwait is derived from the...
i detainees being held in isolation in Guantanamo Bay, Cuba, without charges, without a hearing and without access to a lawyer. According to Peter Honigsberg, a professor of law at the University of San Francisco, Wilner unsuccessfully made two arguments before the Court to hear his case; in his third argument he changed tactics by mentioning US law and the Cuban iguana. Wilner argued, "Anyone, including a federal official, who violates the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
by harming an iguana at Guantanamo, can be fined and prosecuted. Yet the government argues that US law does not apply to protect the human prisoners there". According to Honigsberg, the Supreme Court agreed to hear the case because of this argument.
Decline
In general the species is in decline, more quickly on the mainland than on the outlying islets. The Cuban mainland populations have been declining at a rate of over 1% per year for the last 10 years. The Cuban iguana is no longer found on the northeastern coast of HavanaHavana
Havana is the capital city, province, major port, and leading commercial centre of Cuba. The city proper has a population of 2.1 million inhabitants, and it spans a total of — making it the largest city in the Caribbean region, and the most populous...
, the Hicacos Peninsula
Hicacos Peninsula
Hicacos is a peninsula on Cuba's northern shore, in the province of Matanzas. The resort town of Varadero is located on the peninsula. The name comes from a species of cactus.-Geography:...
, or Cayo Largo, areas where it was found in great numbers some 30 to 40 years ago.
As opposed to other West Indian islands where iguanids are found, consumption of iguana meat is not widespread in Cuba. Certain fishing communities do practice it for subsistence, but for the most part the animal is not eaten by Cubans. According to naturalist Thomas Barbour
Thomas Barbour
Thomas Barbour was an American herpetologist. From 1927 until 1946, he was director of the Museum of Comparative Zoology founded in 1859 by Louis Agassiz at Harvard University in Cambridge, Massachusetts....
, this is based on unfounded superstitious beliefs which suggest that the iguanas emit a dark fluid reminiscent of the black vomit of yellow fever
Yellow fever
Yellow fever is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family....
victims when they are killed. One of the reasons for their decline is habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
caused by the overgrazing of farm animals, housing development, and the building of tourist resorts on the beaches where the animals prefer to build their nests. Populations of iguanas suffer by the direct predation of introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
animals such as rats, cats, and dogs. Feral hogs are responsible for destroying many iguana nest sites which they dig up for eggs. Ant predation of iguana eggs is another threat to the species.
Recovery
All but one of the major iguana concentrations are either partially or fully protected by the Cuban government. Although no captive-breeding program exists within Cuba, the Centro Nacional de Areas Protegidas (the National Center for Protected Areas) has suggested it will explore this route in the future. In 1985 the Cuban government issued a commemorative peso depicting a Cuban iguana on the head side of the coin in an attempt to raise awareness for this animal.In 1993 the San Diego Zoo
San Diego Zoo
The San Diego Zoo in Balboa Park, San Diego, California, is one of the most progressive zoos in the world, with over 4,000 animals of more than 800 species...
experimentally tested the utility of a "head-starting" program for newly hatched Cuban iguanas with funding from the National Science Foundation's Conservation and Restoration Biology Program. "Head-starting" is a process by which the Cuban iguana's eggs are hatched in an incubator and the animals are protected and fed for the first 20 months of their lives. The purpose is to get the animals to a size where they are more capable of fleeing from or fighting off predators. This technique was originally used to protect hatchling sea turtles, Galapagos land iguana
Galapagos Land Iguana
The Galapagos Land Iguana is a species of lizard in the Iguanidae family. It is one of three species of the genus Conolophus...
s, and Ctenosaura bakeri on the island of Utila
Útila
Utila is the third largest of Honduras' Bay Islands, after Roatán and Guanaja, in a region that marks the south end of the Mesoamerican Barrier Reef System, the second-largest in the world...
, but Alberts used it for the first time on a Cyclura species with the Cuban iguana. The purpose was not only to help the Cuban iguana population, but to test the overall effectiveness of headstarting as a conservation strategy for more critically endangered species of Cyclura.
The strategy proved successful, according to Alberts, when the released head-started iguanas reacted to predators, foraged for food, and behaved like their wild-born counterparts. This strategy has been implemented with great success with other critically endangered species of Cyclura and Ctenosaura
Ctenosaura
Ctenosaura is a genus of lizard commonly known as spinytail iguanas. The genus is part of the large lizard family, Iguanidae and is native to Mexico and Central America. The species range in size from about 5 inches to well over one meter. The distinctive feature of this genus is presence of the...
throughout the West Indies and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, notably the Jamaican iguana, Grand Cayman blue iguana, Ricord's iguana
Cyclura ricordi
The Hispaniolan Ground Iguana, Ricord's Ground Iguana, Ricord's Rock Iguana, or Ricord's Iguana is a critically endangered species of rock iguana....
, Allen Cays iguana
Cyclura cychlura inornata
The Allen Cays Rock Iguana is an endangered subspecies of the Northern Bahamian Rock Iguana that is found on Allen Cay in the Bahamas...
, San Salvador iguana, and Anegada iguana
Cyclura pinguis
The Stout Iguana or Anegada Ground Iguana is a critically endangered species of lizard of the genus Cyclura belonging to the Iguanidae family. The species can be found exclusively in the island of Anegada...
.
Footnotes
- Note a:Burton, F. (2004): The 1977 study by Schwartz and Carey included scalation counts for different species of Cyclura, but did not distinguish Cyclura nubila from Cyclura cychlura found in the Bahamas. Fred Burton noted a conspicuously enlarged canthal scaleCanthal scalesIn snakes, the canthals are the scales along the upper surface of the canthus rostralis. They are located behind the level of the prenasal/postnasal suture and before the supraocular. They are also described as being located along the edge of the crown between the internasals and the supraoculars...
in Cyclura cychlura while performing his survey of Cyclura. Burton's conclusion was that in 2 of 38 specemins of Cyclura lewisiBlue IguanaThe Blue Iguana or Grand Cayman Iguana is a critically endangered species of lizard of the genus Cyclura endemic to the island of Grand Cayman. Previously listed as a subspecies of the Cuban Iguana, it was reclassified as a separate species in 2004 because of genetic differences discovered four...
, the fourth auricular row was so reduced as to appear like Cyclura nubila caymanensisCyclura nubila caymanensisThe Lesser Caymans Iguana or Cayman Brac Iguana or Cayman Island Brown Iguana or Sister Isles Iguana is a critically endangered subspecies of the Cuban Iguana...
, and in six of 38 C. n. caymanensis, a complete row of five auriculars was present. The character was intermediate for Cyclura nubila, where 10 of 32 specimens showed a complete auricular row.
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