Central American Squirrel Monkey
Encyclopedia
The Central American squirrel monkey (Saimiri oerstedii) is a squirrel monkey
species from the Pacific coast of Costa Rica and Panama. It is restricted to the northwestern tip of Panama
near the border with Costa Rica
, and the central and southern Pacific
coast of Costa Rica, primarily in Manuel Antonio
and Corcovado National Park
s.
It is a small monkey with an orange back and a distinctive white and black facial mask. It has an omnivorous diet, eating fruits, other plant materials, invertebrate
s and some small vertebrate
s. In turn, it has a number of predators, including raptors
, cats
and snakes. It lives in large groups that typically contain between 20 and 75 monkeys. It has one of the most egalitarian social structures of all monkeys. Females do not form dominance hierarchies, and males only do so at breeding season. Females become sexually mature at 2½ years, and males at 4 to 5 years. Sexually mature females leave the natal group, but males can remain with their natal group their entire life. The Central American squirrel monkey can live for more than 15 years.
The Central American squirrel monkey population declined precipitously after the 1970s. This decline is believed to be caused by deforestation
, hunting, and capture to be kept as pets. Efforts are underway to preserve the species. Despite the threats to the population, in 2008 the International Union for Conservation of Nature (IUCN) upgraded its conservation status from "endangered" to "vulnerable".
, the family of New World monkeys containing squirrel monkeys, capuchin monkey
s, tamarin
s and marmoset
s. Within the family Cebidae, it is a member of the subfamily Saimiriinae, the subfamily containing squirrel monkeys. It is one of five recognized species of squirrel monkey, and the only species occurring outside South America. The Central American Squirrel Monkey is placed in genus Saimiri (Voigt, 1831) along with all the other squirrel monkey species. Among the squirrel monkeys, the Central American squirrel monkey is most closely related to the common squirrel monkey
(Saimiri sciureus) and the bare-eared squirrel monkey
(Saimiri ustus) and these three species form the S. sciureus species group. The binomial name Saimiri oerstedii was given by Johannes Theodor Reinhardt
in honor of his fellow Danish
biologist
Anders Sandøe Ørsted
.
There are two subspecies of the Central American squirrel monkey:
S. o. oerstadii lives in the western Pacific portion of Panama and the Osa Peninsula
area of Costa Rica (including Corcovado National Park), while S. o. citrinellus lives in the Central Pacific portion of Costa Rica. It has been estimated (most recently in 2003) that the remaining wild population of S. o. citrinellus is only 1300 to 1800 individuals.
n squirrel monkeys. While South American squirrel monkeys tend to be primarily greenish in color, the Central American species has an orange back with olive shoulders, hips and tail and white undersides. The hands and feet are also orange. There is a black cap at the top of the head, and a black tip at the end of the tail. Males generally have lighter caps than females. The face is white with black rims around the eyes and black around the nose and mouth.
The two subspecies are similar in coloration, but differ in the shade of the cap. The northern subspecies, living in Central Pacific Costa Rica, has a lighter cap than the southern subspecies, which lives in Panama and in parts of Costa Rica near Panama. The southern subspecies also has more yellowish limbs and underparts.
Adults reach a length of between 266 and 291 mm (10.5 and 11.5 in), excluding tail, and a weight between 600 and 950 g (21.2 and 33.5 oz). The tail is longer than the body, and between 362 and 389 mm (14.3 and 15.3 in) in length. As with other squirrel monkeys, there is considerable sexual dimorphism
. On average, males weigh 16% more than females. Males have an average body weight of 829 g (29.2 oz) and females average 695 g (24.5 oz). Squirrel monkeys have the largest brains of all primates relative to their body size; the Central American squirrel monkey's brain weighs about 25.7 g (0.906540826101377 oz), or about 4% of its body weight. Unlike larger relatives, such as the capuchin
, spider
and howler monkey
s, adult Central American squirrel monkeys do not have a fully prehensile tail, except as newborn infants, and the tail is primarily used to help with balance.
The squirrel monkey groups have a home range of between 35 and 63 hectares (86 to 156 acres). Group ranges can overlap, especially in large, protected areas such as Manuel Antonio National Park. Less overlap occurs in more fragmented areas. Groups can travel between 2500 and 4200 m (8,202.1 and 13,779.5 ft) per day. Unlike some other monkey species, the group does not split into separate foraging groups during the day. Individual monkeys may separate for the main group to engage in different activities for periods of time, and thus the group may be dispersed over an area of up to three acres (1.2 hectares) at any given time. The group tends to sleep in the same trees every night for months at a time, unlike other squirrel monkeys.
There are no dominance hierarchies among the females, and the females do not form coalitions. Males in the group are generally related to each other and thus tend to form strong affiliations, and only form dominance hierarchies during the breeding season. This is especially the case among males of the same age. Neither males nor females are dominant over each other, an egalitarian social system that is unique to Central American squirrel monkeys. In South American species, either the females (S. boliviensis) or males (S. sciureus) are dominant over the other sex, and both sexes form stable dominance hierarchies. Groups of Central American Squirrel Monkeys generally do not compete or fight with each other.
Although South American species of squirrel monkeys often travel with and feed together with capuchin monkeys, the Central American squirrel monkey only rarely associates with the white-headed capuchin
. This appears to be related to the fact that the food the Central American squirrel monkey eats is distributed in smaller, more dispersed patches than that of South American squirrel monkeys. As a result of the different food distribution, associating with capuchin monkeys would impose higher foraging costs for the Central American squirrel monkey than for their South American counterparts. In addition, while male White-headed Capuchins are alert to predators, they devote more attention to detecting rival males than to detecting predators, and relatively less time to detecting predators than their South American counterparts. Therefore, associating with capuchins would provide less predator detection benefits and impose higher foraging costs on the Central American squirrel monkey than on South American squirrel monkeys.
Certain bird species associate with the Central American squirrel monkey. The birds follow the monkeys in an attempt to prey on insects and small vertebrates that the monkeys flush out. At Corcovado National Park, bird species known to regularly follow squirrel monkeys include the Double-toothed Kite
, the Grey-headed Tanager
and the Tawny-winged Woodcreeper
, but other woodcreeper
s and species such as motmot
s and trogon
s do so as well. This activity increases during the wet season, when arthropod
s are harder to find.
The Central American squirrel monkey is omnivorous
. Its diet includes insects and insect larvae (especially grasshopper
s and caterpillar
s), spiders, fruit, leaves, bark, flowers and nectar. It also eats small vertebrate
s, including bats, birds, lizards and tree frogs. It finds its food foraging through the lower and middle levels of the forest, typically between fifteen and thirty feet high. Two-thirds to three-quarters of each day is spent foraging for food. It has difficulty finding its desired food late in the wet season, when fewer arthropods are available.
It has a unique method of capturing Tent-making Bat
s. It looks for roosting bats by looking for their tents (which are made of a folded leaf). When it finds a bat it climbs to a higher level and jumps onto the tent from above, attempting to dislodge the bat. If the fallen bat doesn't fly away in time, the monkey pounces on it on the ground and eats it.
The Central American squirrel monkey is an important seed disperser and a pollinator of certain flowers, including the passion flower
. While it is not a significant agricultural pest, it does sometimes eat corn, coffee, banana
s and mango
s. Other fruits eaten include cecropia
s, legumes, fig
s, palms, cerillo
, quiubra
, yayo flaco
and wild cashew
fruits.
Predator detection by the males becomes particularly important during the period when the infants are born. Raptors spend significantly more time near the squirrel monkey troops during this period, and prey on a significant number of the newborn infants. Other animals that prey on Central American squirrel monkey infants include toucan
s, tayra
s, opossums, coati
s, snakes, and even spider monkey
s.
at virtually the same time. A month or two before the breeding season begins, males become larger. This is not due to extra muscle, but to altered water balance within the male's body. This is caused by conversion of the male hormone testosterone
into estrogen
; thus the more testosterone a male produces, the more he grows in advance of the breeding season. Since males within a group have not been observed fighting over access to females during breeding season, nor attempting to force females to copulate with them, it is believed that female choice determines which males get to breed with females. Females tend to prefer the males that expand the most in advance of breeding season. This may be because the most enlarged males are generally the oldest and the most effective at detecting predators, or it may be a case of runaway intersexual selection
.
Males sometimes leave their group for short periods of time during the breeding season in order to try to mate with females from neighboring groups. Females are receptive to males from other groups, although resident males attempt to repel the intruders. The gestation period
is six months, and the infants are born within a single week during February and March. Typically, a single infant is born.
Only 50% of infants survive more than six months, largely due to predation by birds. The infant remains dependent on its mother for about one year. Females give birth every 12 months, so the prior infant becomes independent at about the same time the new infant is born. Females become sexually mature at 2½ years old, while males become sexually mature at between 4 and 5 years old. The females leave their natal group upon reaching sexual maturity, while males usually remain with their group for their entire lives. This is different from South American squirrel monkey species, where either males disperse from their natal group or both sexes disperse. Males of the same age tend to associate with each other in age cohorts. Upon reaching sexual maturity, an age cohort may choose to leave the group and attempt to oust the males from another group in order to attain increased reproductive opportunities.
The lifespan of the Central American squirrel monkey in the wild is unknown, but captive specimens have been known to live more than 15 years. Other squirrel monkey species are known to be able to live more than 20 years.
and Corcovado National Park
— where it can be seen by visitors, but it is not as commonly seen in these parks as the white-headed capuchin
or the mantled howler
monkeys. It lives lowland forests and is restricted to secondary forest
s and primary forests which have been partially logged
. It requires forests with abundant low and mid-level vegetation and has difficulty surviving in tall, mature, undisturbed forests that lack such vegetation.
and mitochondrial DNA
demonstrated that the Central American squirrel monkey is indeed a separate species that apparently diverged from the South American species long ago - at least 260,000 years ago and possibly more than 4 million years ago.
One popular theory is that squirrel monkeys did live in Colombia during the late Miocene
or Pliocene
and these squirrel monkeys migrated to Central America, becoming the ancestors of the current Central American species. According to this theory, the Guatemalan black howler
migrated to Central America around the same time. Passage through the isthmus
of Panama later closed due to rising oceans, and eventually opened up to another wave of migration about 2 million years ago. These later migrants, ancestors to modern populations of white-headed capuchins, mantled howler
s and Geoffroy's spider monkey
s, out-competed the earlier migrants, leading to the small range of the Central American squirrel monkey and Guatemalan black howler.
The population density has been estimated at 36 monkeys per square kilometer (93 per square mile) in Costa Rica and 130 monkeys per square kilometer (337 per square mile) in Panama. It has been estimated that the population of the Central American squirrel monkey has been reduced from about 200,000 in the 1970s to less than 5000. This is believed to be largely due to deforestation
, hunting
, and capture for the pet
trade. There are significant efforts within Costa Rica to try to preserve this monkey from extinction. A reforestation project within Panama tries to preserve the vanishing population of the Chiriqui Province.
As of 2008, the Central American squirrel monkey is listed as "vulnerable" from a conservation standpoint by the IUCN. This is due to the fact that its range encompasses just 8000 square kilometres (3,088.8 sq mi), its range is fragmented, and it suffers from ongoing habitat loss. This assessment is an improvement from the 2003 assessment, in which the Central American squirrel monkey was listed as "endangered".
Squirrel monkey
The squirrel monkeys are the New World monkeys of the genus Saimiri. They are the only genus in the subfamily Saimirinae.Squirrel monkeys live in the tropical forests of Central and South America in the canopy layer. Most species have parapatric or allopatric ranges in the Amazon, while S...
species from the Pacific coast of Costa Rica and Panama. It is restricted to the northwestern tip of Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
near the border with Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
, and the central and southern Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
coast of Costa Rica, primarily in Manuel Antonio
Manuel Antonio National Park
Manuel Antonio National Park, in Spanish the Parque Nacional Manuel Antonio, is a small National Park in the Central Pacific Conservation Area located on the Pacific coast of Costa Rica, just south of the city of Quepos, Puntarenas, and from the national capital of San José...
and Corcovado National Park
Corcovado National Park
Corcovado National Park is a National Park on the Osa Peninsula in the South West of Costa Rica , which is part of the Osa Conservation Area. It was established on 24 October 1975, and encompasses an area of 425 km² . It is widely considered the crown jewel in the extensive system of national...
s.
It is a small monkey with an orange back and a distinctive white and black facial mask. It has an omnivorous diet, eating fruits, other plant materials, invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s and some small vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s. In turn, it has a number of predators, including raptors
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
, cats
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...
and snakes. It lives in large groups that typically contain between 20 and 75 monkeys. It has one of the most egalitarian social structures of all monkeys. Females do not form dominance hierarchies, and males only do so at breeding season. Females become sexually mature at 2½ years, and males at 4 to 5 years. Sexually mature females leave the natal group, but males can remain with their natal group their entire life. The Central American squirrel monkey can live for more than 15 years.
The Central American squirrel monkey population declined precipitously after the 1970s. This decline is believed to be caused by deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....
, hunting, and capture to be kept as pets. Efforts are underway to preserve the species. Despite the threats to the population, in 2008 the International Union for Conservation of Nature (IUCN) upgraded its conservation status from "endangered" to "vulnerable".
Taxonomy
The Central American squirrel monkey is a member of the family CebidaeCebidae
The Cebidae is one of the five families of New World monkeys now recognised. It includes the capuchin monkeys and squirrel monkeys. These species are found throughout tropical and subtropical South and Central America.-Characteristics:...
, the family of New World monkeys containing squirrel monkeys, capuchin monkey
Capuchin monkey
The capuchins are New World monkeys of the genus Cebus. The range of capuchin monkeys includes Central America and South America as far south as northern Argentina...
s, tamarin
Tamarin
The tamarins are squirrel-sized New World monkeys from the family Callitrichidae in the genus Saguinus. They are closely related to the lion tamarins in the genus Leontopithecus.- Range :...
s and marmoset
Marmoset
Marmosets are the 22 New World monkey species of the genera Callithrix, Cebuella, Callibella, and Mico. All four genera are part of the biological family Callitrichidae. The term marmoset is also used in reference to the Goeldi's Monkey, Callimico goeldii, which is closely related.Most marmosets...
s. Within the family Cebidae, it is a member of the subfamily Saimiriinae, the subfamily containing squirrel monkeys. It is one of five recognized species of squirrel monkey, and the only species occurring outside South America. The Central American Squirrel Monkey is placed in genus Saimiri (Voigt, 1831) along with all the other squirrel monkey species. Among the squirrel monkeys, the Central American squirrel monkey is most closely related to the common squirrel monkey
Common Squirrel Monkey
The common squirrel monkey is a small New World primate from the Cebidae family, and native to the tropical areas of South America.-Location:...
(Saimiri sciureus) and the bare-eared squirrel monkey
Bare-eared Squirrel Monkey
The bare-eared squirrel monkey is a squirrel monkey endemic to Brazil....
(Saimiri ustus) and these three species form the S. sciureus species group. The binomial name Saimiri oerstedii was given by Johannes Theodor Reinhardt
Johannes Theodor Reinhardt
Johannes Theodor Reinhardt was a Danish zoologist and herpetologist. He was the son of Johannes Christopher Hagemann Reinhardt....
in honor of his fellow Danish
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
biologist
Biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...
Anders Sandøe Ørsted
Anders Sandøe Ørsted (botanist)
Anders Sandøe Ørsted, also written as Anders Sandoe Oersted or Anders Sandö Örsted was a Danish botanist, mycologist, zoologist and marine biologist. He was nephew of the brothers physicist H.C...
.
There are two subspecies of the Central American squirrel monkey:
- Black-crowned Central American squirrel monkeyBlack-crowned Central American Squirrel MonkeyThe Black-crowned Central American Squirrel Monkey is a subspecies of the Central American Squirrel Monkey. Its range is restricted to the Pacific coast of western Panama to the western portion of the Chiriqui Province and of southern Costa Rica, south of the Rio Grande de Terraba, including the...
, Saimiri oerstedii oerstedii - Grey-crowned Central American squirrel monkeyGrey-crowned Central American Squirrel MonkeyThe Grey-crowned Central American Squirrel Monkey is a subspecies of the Central American Squirrel Monkey. Its range is restricted to the Pacific coast of central Costa Rica. The northern end of its range is the Rio Tulin and the southern end of its range is the Rio Grande de Terraba...
, Saimiri oerstedii citrinellus
S. o. oerstadii lives in the western Pacific portion of Panama and the Osa Peninsula
Osa Peninsula
The Osa Peninsula is a peninsula located in southwestern Costa Rica, in the Puntarenas Province, on the Pacific Ocean, at . The peninsula was formed geologically by a faulting system that extends north into California....
area of Costa Rica (including Corcovado National Park), while S. o. citrinellus lives in the Central Pacific portion of Costa Rica. It has been estimated (most recently in 2003) that the remaining wild population of S. o. citrinellus is only 1300 to 1800 individuals.
Physical description
The Central American squirrel monkey differs in coloration from South AmericaSouth America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n squirrel monkeys. While South American squirrel monkeys tend to be primarily greenish in color, the Central American species has an orange back with olive shoulders, hips and tail and white undersides. The hands and feet are also orange. There is a black cap at the top of the head, and a black tip at the end of the tail. Males generally have lighter caps than females. The face is white with black rims around the eyes and black around the nose and mouth.
The two subspecies are similar in coloration, but differ in the shade of the cap. The northern subspecies, living in Central Pacific Costa Rica, has a lighter cap than the southern subspecies, which lives in Panama and in parts of Costa Rica near Panama. The southern subspecies also has more yellowish limbs and underparts.
Adults reach a length of between 266 and 291 mm (10.5 and 11.5 in), excluding tail, and a weight between 600 and 950 g (21.2 and 33.5 oz). The tail is longer than the body, and between 362 and 389 mm (14.3 and 15.3 in) in length. As with other squirrel monkeys, there is considerable sexual dimorphism
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:...
. On average, males weigh 16% more than females. Males have an average body weight of 829 g (29.2 oz) and females average 695 g (24.5 oz). Squirrel monkeys have the largest brains of all primates relative to their body size; the Central American squirrel monkey's brain weighs about 25.7 g (0.906540826101377 oz), or about 4% of its body weight. Unlike larger relatives, such as the capuchin
Capuchin monkey
The capuchins are New World monkeys of the genus Cebus. The range of capuchin monkeys includes Central America and South America as far south as northern Argentina...
, spider
Spider monkey
Spider monkeys of the genus Ateles are New World monkeys in the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil...
and howler monkey
Howler monkey
Howler monkeys are among the largest of the New World monkeys. Fifteen species are currently recognised. Previously classified in the family Cebidae, they are now placed in the family Atelidae. These monkeys are native to South and Central American forests...
s, adult Central American squirrel monkeys do not have a fully prehensile tail, except as newborn infants, and the tail is primarily used to help with balance.
Social structure
The Central American squirrel monkey is arboreal and diurnal, and most often moves through the trees on four legs (quadrupedal locomotion). It lives in groups containing several adult males, adult females and juveniles. The group size tends to be smaller than that of South American squirrel monkeys, but is still larger than for many other New World monkey species. The group generally numbers between 20 and 75 monkeys, with a mean of 41 monkeys. Groups in excess of 100 sometimes occur, but these are believed to be temporary mergers of two groups. On average, groups contain about 60% more females than males.The squirrel monkey groups have a home range of between 35 and 63 hectares (86 to 156 acres). Group ranges can overlap, especially in large, protected areas such as Manuel Antonio National Park. Less overlap occurs in more fragmented areas. Groups can travel between 2500 and 4200 m (8,202.1 and 13,779.5 ft) per day. Unlike some other monkey species, the group does not split into separate foraging groups during the day. Individual monkeys may separate for the main group to engage in different activities for periods of time, and thus the group may be dispersed over an area of up to three acres (1.2 hectares) at any given time. The group tends to sleep in the same trees every night for months at a time, unlike other squirrel monkeys.
There are no dominance hierarchies among the females, and the females do not form coalitions. Males in the group are generally related to each other and thus tend to form strong affiliations, and only form dominance hierarchies during the breeding season. This is especially the case among males of the same age. Neither males nor females are dominant over each other, an egalitarian social system that is unique to Central American squirrel monkeys. In South American species, either the females (S. boliviensis) or males (S. sciureus) are dominant over the other sex, and both sexes form stable dominance hierarchies. Groups of Central American Squirrel Monkeys generally do not compete or fight with each other.
Although South American species of squirrel monkeys often travel with and feed together with capuchin monkeys, the Central American squirrel monkey only rarely associates with the white-headed capuchin
White-headed Capuchin
The white-headed capuchin , also known as the white-faced capuchin or white-throated capuchin, is a medium-sized New World monkey of the family Cebidae, subfamily Cebinae...
. This appears to be related to the fact that the food the Central American squirrel monkey eats is distributed in smaller, more dispersed patches than that of South American squirrel monkeys. As a result of the different food distribution, associating with capuchin monkeys would impose higher foraging costs for the Central American squirrel monkey than for their South American counterparts. In addition, while male White-headed Capuchins are alert to predators, they devote more attention to detecting rival males than to detecting predators, and relatively less time to detecting predators than their South American counterparts. Therefore, associating with capuchins would provide less predator detection benefits and impose higher foraging costs on the Central American squirrel monkey than on South American squirrel monkeys.
Certain bird species associate with the Central American squirrel monkey. The birds follow the monkeys in an attempt to prey on insects and small vertebrates that the monkeys flush out. At Corcovado National Park, bird species known to regularly follow squirrel monkeys include the Double-toothed Kite
Double-toothed Kite
The Double-toothed Kite is a species of bird of prey in the Accipitridae family. It is found in Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad and Tobago, and Venezuela.This fairly...
, the Grey-headed Tanager
Grey-headed Tanager
The Grey-headed Tanager is a species of bird in the Thraupidae family, the only one in the genus Eucometis....
and the Tawny-winged Woodcreeper
Tawny-winged Woodcreeper
The Tawny-winged Woodcreeper is a species of bird in the Dendrocolaptinae subfamily, New World woodcreepers.It is found in Belize, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, and Panama....
, but other woodcreeper
Woodcreeper
The woodcreepers comprise a subfamily of sub-oscine passerine birds endemic to the Neotropics. They have traditionally been considered a distinct family Dendrocolaptidae, but most authorities now place them as a subfamily of the ovenbirds...
s and species such as motmot
Motmot
The motmots or Momotidae are a family of birds in the near passerine order Coraciiformes, which also includes the kingfishers, bee-eaters and rollers. All extant motmots are restricted to woodland or forest in the Neotropics, and the largest diversity is in Middle America. They have a colourful...
s and trogon
Trogon
The trogons and quetzals are birds in the order Trogoniformes which contains only one family, the Trogonidae. The family contains 39 species in eight genera. The fossil record of the trogons dates back 49 million years to the mid-Eocene. They might constitute a member of the basal radiation of...
s do so as well. This activity increases during the wet season, when arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s are harder to find.
Diet
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
. Its diet includes insects and insect larvae (especially grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s and caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s), spiders, fruit, leaves, bark, flowers and nectar. It also eats small vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s, including bats, birds, lizards and tree frogs. It finds its food foraging through the lower and middle levels of the forest, typically between fifteen and thirty feet high. Two-thirds to three-quarters of each day is spent foraging for food. It has difficulty finding its desired food late in the wet season, when fewer arthropods are available.
It has a unique method of capturing Tent-making Bat
Tent-making Bat
The Tent-making Bat, Uroderma bilobatum, is a bat species from South and Central America. It lives in hollowed out trees. It is sometimes speculated that the bat is green in color, even though it is only thought so because of the "tent" the bat makes is made out a leaf that is green in color, in...
s. It looks for roosting bats by looking for their tents (which are made of a folded leaf). When it finds a bat it climbs to a higher level and jumps onto the tent from above, attempting to dislodge the bat. If the fallen bat doesn't fly away in time, the monkey pounces on it on the ground and eats it.
The Central American squirrel monkey is an important seed disperser and a pollinator of certain flowers, including the passion flower
Passion flower
Passiflora, known also as the passion flowers or passion vines, is a genus of about 500 species of flowering plants, the namesakes of the family Passifloraceae. They are mostly vines, with some being shrubs, and a few species being herbaceous. For information about the fruit of the passiflora...
. While it is not a significant agricultural pest, it does sometimes eat corn, coffee, banana
Banana
Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....
s and mango
Mango
The mango is a fleshy stone fruit belonging to the genus Mangifera, consisting of numerous tropical fruiting trees in the flowering plant family Anacardiaceae. The mango is native to India from where it spread all over the world. It is also the most cultivated fruit of the tropical world. While...
s. Other fruits eaten include cecropia
Cecropia
Cecropia is a Neotropical genus presently consisting of sixty-one recognized species with a highly distinctive lineage of dioecious trees....
s, legumes, fig
Ficus
Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...
s, palms, cerillo
Symphonia globulifera
Symphonia globulifera is a timber tree native to Central America, South America and Africa. This plant also used as a medicinal plant and ornamental plant.-Distribution:Native:...
, quiubra
Pseudolmedia
Pseudolmedia is a flowering plant genus in the mulberry family . They are known in Latin America as lechechiva and used for timber, construction wood, and sometimes in folk medicine.Species include:...
, yayo flaco
Xylopia
Xylopia is a genus of plant in family Annonaceae. This genus is solely composed of trees, distribution of which is pantropical . It contains the following species :* Xylopia africana, Oliv....
and wild cashew
Cashew
The cashew is a tree in the family Anacardiaceae. Its English name derives from the Portuguese name for the fruit of the cashew tree, caju, which in turn derives from the indigenous Tupi name, acajú. It is now widely grown in tropical climates for its cashew nuts and cashew apples.-Etymology:The...
fruits.
Communication
The Central American squirrel monkey is noisy. It makes many squeals, whistles and chirps. It also travels through the forest noisily, disturbing vegetation as it moves through. Its has four main calls, which have been described as a "smooth chuck", a "bent mask chuck", a "peep" and a "twitter".Predators
Predators of the Central American squirrel monkey include birds of prey, cats and snakes. Constricting and venomous snakes both prey on squirrel monkeys. Raptors are particularly effective predators of Central American squirrel monkeys. The oldest males bear most of the responsibility for detecting predators. When a Central American squirrel monkey detects a raptor, it gives a high-pitched alarm peep and dives for cover. All other squirrel monkeys that hear the alarm call also dive for cover. The monkeys are particularly cautious about raptors, and give alarms when they detect any raptor-like object, including small airplanes and even falling branches and large leaves.Predator detection by the males becomes particularly important during the period when the infants are born. Raptors spend significantly more time near the squirrel monkey troops during this period, and prey on a significant number of the newborn infants. Other animals that prey on Central American squirrel monkey infants include toucan
Toucan
Toucans are members of the family Ramphastidae of near passerine birds from the Neotropics. The family is most closely related to the American barbets. They are brightly marked and have large, often colorful bills. The family includes five genera and about forty different species...
s, tayra
Tayra
The tayra , also known as the Tolomuco or Perico ligero in Central America, and San Hol or viejo de monte in the Yucatan Peninsula is an omnivorous animal from the weasel family Mustelidae. It is the only species in the genus Eira...
s, opossums, coati
Coati
Coatis, genera Nasua and Nasuella, also known as the Brazilian aardvark, Mexican tejón, hog-nosed coon, pizotes, crackoons and snookum bears, are members of the raccoon family . They are diurnal mammals native to South America, Central America, and south-western North America...
s, snakes, and even spider monkey
Spider monkey
Spider monkeys of the genus Ateles are New World monkeys in the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil...
s.
Reproduction
The breeding season for the Central American squirrel monkey is in September. All females come into estrusEstrous cycle
The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases or pregnancies...
at virtually the same time. A month or two before the breeding season begins, males become larger. This is not due to extra muscle, but to altered water balance within the male's body. This is caused by conversion of the male hormone testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
into estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
; thus the more testosterone a male produces, the more he grows in advance of the breeding season. Since males within a group have not been observed fighting over access to females during breeding season, nor attempting to force females to copulate with them, it is believed that female choice determines which males get to breed with females. Females tend to prefer the males that expand the most in advance of breeding season. This may be because the most enlarged males are generally the oldest and the most effective at detecting predators, or it may be a case of runaway intersexual selection
Sexual selection
Sexual selection, a concept introduced by Charles Darwin in his 1859 book On the Origin of Species, is a significant element of his theory of natural selection...
.
Males sometimes leave their group for short periods of time during the breeding season in order to try to mate with females from neighboring groups. Females are receptive to males from other groups, although resident males attempt to repel the intruders. The gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
is six months, and the infants are born within a single week during February and March. Typically, a single infant is born.
Only 50% of infants survive more than six months, largely due to predation by birds. The infant remains dependent on its mother for about one year. Females give birth every 12 months, so the prior infant becomes independent at about the same time the new infant is born. Females become sexually mature at 2½ years old, while males become sexually mature at between 4 and 5 years old. The females leave their natal group upon reaching sexual maturity, while males usually remain with their group for their entire lives. This is different from South American squirrel monkey species, where either males disperse from their natal group or both sexes disperse. Males of the same age tend to associate with each other in age cohorts. Upon reaching sexual maturity, an age cohort may choose to leave the group and attempt to oust the males from another group in order to attain increased reproductive opportunities.
The lifespan of the Central American squirrel monkey in the wild is unknown, but captive specimens have been known to live more than 15 years. Other squirrel monkey species are known to be able to live more than 20 years.
Distribution and habitat
The Central American squirrel monkey has a restricted distribution in Costa Rica and Panama. It lives only near the Pacific coast. Its range covers Central Pacific Costa Rica in the north through western Panama. It lives in two of Costa Rica's national parks — Manuel Antonio National ParkManuel Antonio National Park
Manuel Antonio National Park, in Spanish the Parque Nacional Manuel Antonio, is a small National Park in the Central Pacific Conservation Area located on the Pacific coast of Costa Rica, just south of the city of Quepos, Puntarenas, and from the national capital of San José...
and Corcovado National Park
Corcovado National Park
Corcovado National Park is a National Park on the Osa Peninsula in the South West of Costa Rica , which is part of the Osa Conservation Area. It was established on 24 October 1975, and encompasses an area of 425 km² . It is widely considered the crown jewel in the extensive system of national...
— where it can be seen by visitors, but it is not as commonly seen in these parks as the white-headed capuchin
White-headed Capuchin
The white-headed capuchin , also known as the white-faced capuchin or white-throated capuchin, is a medium-sized New World monkey of the family Cebidae, subfamily Cebinae...
or the mantled howler
Mantled Howler
The mantled howler , or golden-mantled howling monkey, is a species of howler monkey, a type of New World monkey, from Central and South America. It is one of the monkey species most often seen and heard in the wild in Central America...
monkeys. It lives lowland forests and is restricted to secondary forest
Secondary forest
A secondary forest is a forest or woodland area which has re-grown after a major disturbance such as fire, insect infestation, timber harvest or windthrow, until a long enough period has passed so that the effects of the disturbance are no longer evident...
s and primary forests which have been partially logged
Logging
Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks.In forestry, the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard...
. It requires forests with abundant low and mid-level vegetation and has difficulty surviving in tall, mature, undisturbed forests that lack such vegetation.
Conservation status
It was once believed that the Central American squirrel monkey was just a population of a South American species of squirrel monkey brought to Central America by humans. Evidence for this theory included the very small range of the Central American squirrel monkey and the large gap from the range of any other squirrel monkey species. A study of nuclearNuclear DNA
Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...
and 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...
demonstrated that the Central American squirrel monkey is indeed a separate species that apparently diverged from the South American species long ago - at least 260,000 years ago and possibly more than 4 million years ago.
One popular theory is that squirrel monkeys did live in Colombia during the late Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
or Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
and these squirrel monkeys migrated to Central America, becoming the ancestors of the current Central American species. According to this theory, the Guatemalan black howler
Guatemalan Black Howler
The Guatemalan black howler, or Yucatan black howler, is a species of howler monkey, a type of New World monkey, from Central America. It is found in Belize, Guatemala and Mexico, in and near the Yucatan Peninsula. It lives in evergreen, semi-deciduous and lowland rain forests...
migrated to Central America around the same time. Passage through the isthmus
Isthmus
An isthmus is a narrow strip of land connecting two larger land areas usually with waterforms on either side.Canals are often built through isthmuses where they may be particularly advantageous to create a shortcut for marine transportation...
of Panama later closed due to rising oceans, and eventually opened up to another wave of migration about 2 million years ago. These later migrants, ancestors to modern populations of white-headed capuchins, mantled howler
Mantled Howler
The mantled howler , or golden-mantled howling monkey, is a species of howler monkey, a type of New World monkey, from Central and South America. It is one of the monkey species most often seen and heard in the wild in Central America...
s and Geoffroy's spider monkey
Geoffroy's Spider Monkey
Geoffroy's spider monkey, Ateles geoffroyi, also known as black-handed spider monkey, is a species of spider monkey, a type of New World monkey, from Central America, parts of Mexico and possibly a small portion of Colombia. There are at least five subspecies. Some primatologists classify the...
s, out-competed the earlier migrants, leading to the small range of the Central American squirrel monkey and Guatemalan black howler.
The population density has been estimated at 36 monkeys per square kilometer (93 per square mile) in Costa Rica and 130 monkeys per square kilometer (337 per square mile) in Panama. It has been estimated that the population of the Central American squirrel monkey has been reduced from about 200,000 in the 1970s to less than 5000. This is believed to be largely due to deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....
, hunting
Hunting
Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...
, and capture for the pet
Pet
A pet is a household animal kept for companionship and a person's enjoyment, as opposed to wild animals or to livestock, laboratory animals, working animals or sport animals, which are kept for economic or productive reasons. The most popular pets are noted for their loyal or playful...
trade. There are significant efforts within Costa Rica to try to preserve this monkey from extinction. A reforestation project within Panama tries to preserve the vanishing population of the Chiriqui Province.
As of 2008, the Central American squirrel monkey is listed as "vulnerable" from a conservation standpoint by the IUCN. This is due to the fact that its range encompasses just 8000 square kilometres (3,088.8 sq mi), its range is fragmented, and it suffers from ongoing habitat loss. This assessment is an improvement from the 2003 assessment, in which the Central American squirrel monkey was listed as "endangered".
External links
- ARKive - images and movies of the red-backed squirrel monkey (Saimiri oerstedii)
- ASCOMOTI Foundation for Preservation of the Central American Squirrel Monkey (mono titi)
- Infonatura
- Saimiri Wildlife