Alsophis antiguae
Encyclopedia
The Antiguan Racer is a harmless rear-fanged (opisthoglyphous) grey-brown snake found only on Great Bird Island off the coast of Antigua
, a small Caribbean island, thus colloquially named the "Antigua Racer Snake". It is thought to be the rarest snake in the world. However, in the last 15 years, conservation efforts have boosted numbers from an estimated 50 to some 500 snakes.
which belongs to the family Colubridae, which includes about half of the world's known snake species. It belongs to the genus Alsophis
, which contains several species of West Indian racers. Most of the members of its genus are threatened or extinct.
. The adult racer is about one meter long, with females being larger than the males. The males are a dark brown with light creamy markings, while the females are silvery-gray with pale brown patches and markings. Females also have larger heads than the males.
, a small island three kilometers off of the northeast coast of Antigua
. The island is extremely small at only 20 acres (80,937.2 m²). It prefers to live in shady areas with logs and dense undergrowth, although it is often found on sandbars, rocky ridges, and forests.
The racer primarily eats a diet of lizards, including the local Antiguan Ground Lizard. While the species sometimes hunts for its food, it is typically an ambush predator, waiting for prey with most of its body buried beneath leaves. The racer typically eats a lizard once every two weeks.
, the Antiguan Racers were numerous and widespread. The thick forest that covered the island teemed with lizards, the snakes' favored prey, and the racer had no natural predators to threaten them.
In the late 15th century, European settlers began to colonize and develop Antigua and Barbuda
for huge plantations of sugar cane. The ships which brought slaves to the island also brought rats. Feasting on the sugar cane and, among other things, the eggs of the Antiguan Racer, the rat population rocketed. By the end of the 19th century, the island was overpopulated with rats.
The plantation
owners, desperate to rid themselves of the rats, came up with a plan to introduce Asian mongooses to kill the rats. However, they failed to realize that black rat
s (Rattus rattus) are mainly nocturnal, while the mongooses prefer to hunt during the day. Instead of eating the rats, the mongooses instead ate the native birds, frogs and Antiguan Racers. Within sixty years, the snake had vanished completely from Antigua and most of its offshore islands and many believed that it had become extinct.
However, a few Antiguan Racers survived on a tiny mongoose-free island known Great Bird Island
. In the early 1990s, a local naturalist from the Island Resources Foundation met a zoologist from Fauna & Flora International. Together, they visited Great Bird Island and rediscovered the snake. However, there were only 50 snakes alive in 1995.
Conservation work quickly got underway with surveys of the snake's biology. In December 1995, rat poison was laid across Great Bird Island to eliminate the rats which were threatening the racers. The effort succeeded. In 1996, five adult racers were collected and sent to the Jersey Zoo for the first attempt at captive breeding. The female racers laid eleven eggs with five hatching, but proved to be difficult to keep in captivity due to their feeding habits and low resistance to diseases. Nine of the ten captive racers died because of the common snake mite
.
However, the eradication of rats and mongooses on Great Bird Island led to a population explosion, with the number of racers on the island doubling in two years. However, 20% of the racers were underweight because of the lack of number of lizards to maintain the population levels. Efforts began to clean other offshore islands of Antigua of rats and mongooses to reintroduce the snake so that the population can continue to grow.
The Antiguan Racer is believed to be the world's most endangered snake. It is currently threatened by hurricanes, such as Hurricane Luis
and Hurricane Georges
, flooding, drought, and inbreeding due to low genetic diversity.
Antigua
Antigua , also known as Waladli, is an island in the West Indies, in the Leeward Islands in the Caribbean region, the main island of the country of Antigua and Barbuda. Antigua means "ancient" in Spanish and was named by Christopher Columbus after an icon in Seville Cathedral, Santa Maria de la...
, a small Caribbean island, thus colloquially named the "Antigua Racer Snake". It is thought to be the rarest snake in the world. However, in the last 15 years, conservation efforts have boosted numbers from an estimated 50 to some 500 snakes.
Taxonomy
The Antiguan Racer is a snakeSnake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
which belongs to the family Colubridae, which includes about half of the world's known snake species. It belongs to the genus Alsophis
Alsophis
Alsophis is a genus of snake in the Colubridae family. They are among those snakes called "racers" and occur throughout the Caribbean. Alsophis snakes are the world’s rarest form of snake, and are currently critically endangered. Alsophis snakes are small rear fanged snakes, proving them harmless...
, which contains several species of West Indian racers. Most of the members of its genus are threatened or extinct.
Description
This racer exhibits sexual dimorphismSexual 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:...
. The adult racer is about one meter long, with females being larger than the males. The males are a dark brown with light creamy markings, while the females are silvery-gray with pale brown patches and markings. Females also have larger heads than the males.
Distribution and habitat
The Antiguan Racer is only found on Great Bird IslandGreat Bird Island, Antigua
Great Bird Island is a tiny islet lying almost three kilometres north-east of Antigua. Measuring just , smaller than most city parks, it is the only place on Earth where you can see an Antiguan Racer in the wild. The entire world population of this snake lives on the island...
, a small island three kilometers off of the northeast coast of Antigua
Antigua
Antigua , also known as Waladli, is an island in the West Indies, in the Leeward Islands in the Caribbean region, the main island of the country of Antigua and Barbuda. Antigua means "ancient" in Spanish and was named by Christopher Columbus after an icon in Seville Cathedral, Santa Maria de la...
. The island is extremely small at only 20 acres (80,937.2 m²). It prefers to live in shady areas with logs and dense undergrowth, although it is often found on sandbars, rocky ridges, and forests.
Ecology and behavior
The Antiguan Racer is harmless to humans and has a gentle temperament. It is diurnal, being active from dawn to dusk except for a rest around mid-day. At night, it rests in a hidden shelter. The Antiguan Racer has a poor resistance to common diseases not found in Antigua, which has ended some attempts at captive breeding.The racer primarily eats a diet of lizards, including the local Antiguan Ground Lizard. While the species sometimes hunts for its food, it is typically an ambush predator, waiting for prey with most of its body buried beneath leaves. The racer typically eats a lizard once every two weeks.
Relationship with Humans
In the centuries before the Europeans arrived in AntiguaAntigua and Barbuda
Antigua and Barbuda is a twin-island nation lying between the Caribbean Sea and the Atlantic Ocean. It consists of two major inhabited islands, Antigua and Barbuda, and a number of smaller islands...
, the Antiguan Racers were numerous and widespread. The thick forest that covered the island teemed with lizards, the snakes' favored prey, and the racer had no natural predators to threaten them.
In the late 15th century, European settlers began to colonize and develop Antigua and Barbuda
Antigua and Barbuda
Antigua and Barbuda is a twin-island nation lying between the Caribbean Sea and the Atlantic Ocean. It consists of two major inhabited islands, Antigua and Barbuda, and a number of smaller islands...
for huge plantations of sugar cane. The ships which brought slaves to the island also brought rats. Feasting on the sugar cane and, among other things, the eggs of the Antiguan Racer, the rat population rocketed. By the end of the 19th century, the island was overpopulated with rats.
The plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
owners, desperate to rid themselves of the rats, came up with a plan to introduce Asian mongooses to kill the rats. However, they failed to realize that black rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
s (Rattus rattus) are mainly nocturnal, while the mongooses prefer to hunt during the day. Instead of eating the rats, the mongooses instead ate the native birds, frogs and Antiguan Racers. Within sixty years, the snake had vanished completely from Antigua and most of its offshore islands and many believed that it had become extinct.
However, a few Antiguan Racers survived on a tiny mongoose-free island known Great Bird Island
Great Bird Island, Antigua
Great Bird Island is a tiny islet lying almost three kilometres north-east of Antigua. Measuring just , smaller than most city parks, it is the only place on Earth where you can see an Antiguan Racer in the wild. The entire world population of this snake lives on the island...
. In the early 1990s, a local naturalist from the Island Resources Foundation met a zoologist from Fauna & Flora International. Together, they visited Great Bird Island and rediscovered the snake. However, there were only 50 snakes alive in 1995.
Conservation work quickly got underway with surveys of the snake's biology. In December 1995, rat poison was laid across Great Bird Island to eliminate the rats which were threatening the racers. The effort succeeded. In 1996, five adult racers were collected and sent to the Jersey Zoo for the first attempt at captive breeding. The female racers laid eleven eggs with five hatching, but proved to be difficult to keep in captivity due to their feeding habits and low resistance to diseases. Nine of the ten captive racers died because of the common snake mite
Mite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
.
However, the eradication of rats and mongooses on Great Bird Island led to a population explosion, with the number of racers on the island doubling in two years. However, 20% of the racers were underweight because of the lack of number of lizards to maintain the population levels. Efforts began to clean other offshore islands of Antigua of rats and mongooses to reintroduce the snake so that the population can continue to grow.
The Antiguan Racer is believed to be the world's most endangered snake. It is currently threatened by hurricanes, such as Hurricane Luis
Hurricane Luis
Hurricane Luis was one of the deadliest and most destructive hurricanes of the 1995 Atlantic hurricane season, with maximum sustained winds of 140 mph . The storm was the twelfth tropical storm, sixth hurricane, and second major hurricane of the season...
and Hurricane Georges
Hurricane Georges
Hurricane Georges was a very destructive, powerful and long-lived Cape Verde-type Category 4 hurricane. Georges was the seventh tropical storm, fourth hurricane, and second major hurricane of the 1998 Atlantic hurricane season...
, flooding, drought, and inbreeding due to low genetic diversity.