Brown-throated Three-toed Sloth
Encyclopedia
The brown-throated sloth (Bradypus variegatus) is a species
of three-toed sloth
. It is the most common of the four species of three-toed sloth, and is found in the forests of South and Central America.
The brown-throated sloth is of similar size and build to most other species of three-toed sloth, with both males and females being 42 to 80 cm (16.5 to 31.5 ) in total body length. The tail is relatively short, only 2.5 to 9 cm (0.984251968503937 to 3.5 ) long. Adults weigh from 2.25 to 6.3 kg (5 to 13.9 ), with no significant size difference between males and females. Each foot has three fingers, ending in long, curved claws, which are 7 to 8 cm (2.8 to 3.1 ) long on the forefeet, and 5 to 5.5 cm (2 to 2.2 ) on the hindfeet.
The head is rounded, with a blunt nose and inconspicuous ears. As with other sloths, the brown-throated sloth has no incisor or canine teeth, and the cheek teeth are simple and peg like. They have no gall bladder, cecum
, or appendix
.
The brown-throated sloth has grayish brown to beige color fur over the body, with darker brown fur on the throat, the sides of the face, and the forehead. The face is generally paler in color, with a stripe of very dark fur running beneath the eyes.
The guard hair
s are very coarse and stiff, and overly a much softer layer of dense under-fur. The hairs are unusual in lacking a central medulla, and have numerous microscopic cracks across their surface. These cracks are host to a number of commensal
species of algae
, including Rufusia pillicola, Dictyococcus bradypodis, and Chlorococcum choloepodis. The algae are generally absent in the hair of young sloths, and may also be absent in particularly old individuals, where the outer cuticle of the hair has been lost.
Over parts of its range, the Brown-throated Sloth overlaps the range of Hoffmann's Two-toed Sloth
. Where this overlap occurs, the three-toed sloth tends to be smaller and more numerous than its relative, being more active in moving through the forest and maintaining more diurnal activity.
in the north, through Nicaragua
, Costa Rica
and Panama
into Venezuela
, Colombia
, Ecuador
, Bolivia
, and eastern Peru
. It is probably not found north of the Amazon Rainforest
or east of the Rio Negro, although its similarity to the pale-throated sloth found in these regions has led to some confusion in the past.
It is found in many different kinds of environments, including evergreen and dry forests and in highly perturbed natural areas. It is generally found from sea level to 1200 metres (3,937 ft), although some individuals have been reported from much higher elevations.
Brown-throated sloths inhabit the high canopy of the forest, where they eat young leaves from a wide range of different trees. They are solitary animals, and do not travel far, with home ranges of only around 0.5 to 9 ha (1.2 to 22.2 ), depending on the local environment. Within a typical, 5 hectares (12.4 acre) range, a brown-throated sloth will visit around 40 trees, and may specialise on one particular species, even spending up to 20% of its time in a single specific tree. Thus, although the species are generalists, individual sloths may feed on a relatively narrow range of leaf types.
In addition to the algae in their fur, brown-throated sloths also live commensally with a species of moth, Cryptoses choloepi
, which lives in their fur, and lays its eggs in the dung.
Jaguar
s and Harpy Eagles are among the few natural predators of the brown-throated sloth. The Yellow-headed Caracara
has been observed to forage for small invertebrates in the fur of the sloths, apparently without the sloth being disturbed by the attention.
The female of the species is known to emit a loud, shrill scream during the mating season to attract males. It is a cry that sounds like "ay ay". This scream has been remarked to sound exactly like that of a woman screaming. The male can be identified by a black stripe surrounded by orange fur on its back between the shoulders.
The female's mammary gland
s do not store significant quantities of milk as most other mammals do, since the lactating infant sloth remains attached to the nipple at all times, and consumes the milk as soon as it is generated. The young begin to take solid food as early as four days after birth, initially licking particles of food from their mother's mouths. This process apparently allows them to quickly identify edible leaves, and young sloths typically have the same preferences for leaf types as their mothers.
Brown-throated sloths have lived for at least three years in captivity.
The closest living relative of the species is the pale-throated sloth, which has a very similar appearance, except for the color of the fur around the throat. The two species are estimated to have diverged just 400,000 years ago, whereas their ancestors diverged from the maned sloth over 7 million years ago.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of three-toed sloth
Three-toed sloth
The three-toed sloths are tree-living mammals from South and Central America. They are the only members of the genus Bradypus and the family Bradypodidae. There are four living species of three-toed sloths...
. It is the most common of the four species of three-toed sloth, and is found in the forests of South and Central America.
Description
The head is rounded, with a blunt nose and inconspicuous ears. As with other sloths, the brown-throated sloth has no incisor or canine teeth, and the cheek teeth are simple and peg like. They have no gall bladder, cecum
Cecum
The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...
, or appendix
Vermiform appendix
The appendix is a blind-ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouchlike structure of the colon...
.
The brown-throated sloth has grayish brown to beige color fur over the body, with darker brown fur on the throat, the sides of the face, and the forehead. The face is generally paler in color, with a stripe of very dark fur running beneath the eyes.
The guard hair
Guard hair
Guard hairs are the longest, coarsest hairs in a mammal's coat, forming the topcoat . They taper to a point and protect the undercoat from the elements. They are often water repellent and stick out above the rest of the coat...
s are very coarse and stiff, and overly a much softer layer of dense under-fur. The hairs are unusual in lacking a central medulla, and have numerous microscopic cracks across their surface. These cracks are host to a number of commensal
Commensalism
In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...
species of algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, including Rufusia pillicola, Dictyococcus bradypodis, and Chlorococcum choloepodis. The algae are generally absent in the hair of young sloths, and may also be absent in particularly old individuals, where the outer cuticle of the hair has been lost.
Over parts of its range, the Brown-throated Sloth overlaps the range of Hoffmann's Two-toed Sloth
Hoffmann's Two-toed Sloth
Hoffmann's two-toed sloth is a species of sloth from Central and South America. It is a solitary nocturnal and arboreal animal, found in mature and secondary rainforests and deciduous forests...
. Where this overlap occurs, the three-toed sloth tends to be smaller and more numerous than its relative, being more active in moving through the forest and maintaining more diurnal activity.
Distribution and habitat
The Brown-throated Sloth is the most widespread and common of the three-toed sloths. It is found from HondurasHonduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...
in the north, through Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
, 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 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...
into Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
, Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
, and eastern Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
. It is probably not found north of the Amazon Rainforest
Amazon Rainforest
The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...
or east of the Rio Negro, although its similarity to the pale-throated sloth found in these regions has led to some confusion in the past.
It is found in many different kinds of environments, including evergreen and dry forests and in highly perturbed natural areas. It is generally found from sea level to 1200 metres (3,937 ft), although some individuals have been reported from much higher elevations.
Behaviour and diet
Brown-throated sloths spend 15 to 18 hours every day sleeping, and are active for only a few brief periods, which may be during either the day or night. Although they can walk along the ground, and even swim, they spend most of their lives in the high branches of trees, descending once every eight days or so to defecate in the soil. Adult animals are solitary, except when raising young, and males have been observed to fight one another using their foreclaws.Brown-throated sloths inhabit the high canopy of the forest, where they eat young leaves from a wide range of different trees. They are solitary animals, and do not travel far, with home ranges of only around 0.5 to 9 ha (1.2 to 22.2 ), depending on the local environment. Within a typical, 5 hectares (12.4 acre) range, a brown-throated sloth will visit around 40 trees, and may specialise on one particular species, even spending up to 20% of its time in a single specific tree. Thus, although the species are generalists, individual sloths may feed on a relatively narrow range of leaf types.
Cryptoses choloepi
Cryptoses choloepi is a sloth moth in the snout moth family that lives exclusively in the fur of sloths, mammals found in South and Central America....
, which lives in their fur, and lays its eggs in the dung.
Jaguar
Jaguar
The jaguar is a big cat, a feline in the Panthera genus, and is the only Panthera species found in the Americas. The jaguar is the third-largest feline after the tiger and the lion, and the largest in the Western Hemisphere. The jaguar's present range extends from Southern United States and Mexico...
s and Harpy Eagles are among the few natural predators of the brown-throated sloth. The Yellow-headed Caracara
Yellow-headed Caracara
The Yellow-headed Caracara is a bird of prey in the family Falconidae. It is found in tropical and subtropical South America and the southern portion of Central America...
has been observed to forage for small invertebrates in the fur of the sloths, apparently without the sloth being disturbed by the attention.
The female of the species is known to emit a loud, shrill scream during the mating season to attract males. It is a cry that sounds like "ay ay". This scream has been remarked to sound exactly like that of a woman screaming. The male can be identified by a black stripe surrounded by orange fur on its back between the shoulders.
Reproduction
Studies of the brown-throated sloth indicate that mating is most common between January and March in at least the northern parts of its range, but this may vary elsewhere. Gestation lasts at least seven months, and the single young is born fully furred and clawed. Young sloths cling to the mother's underside for five months or more, even though they are fully weaned after just four to five weeks.The female's mammary gland
Mammary gland
A mammary gland is an organ in mammals that produces milk to feed young offspring. Mammals get their name from the word "mammary". In ruminants such as cows, goats, and deer, the mammary glands are contained in their udders...
s do not store significant quantities of milk as most other mammals do, since the lactating infant sloth remains attached to the nipple at all times, and consumes the milk as soon as it is generated. The young begin to take solid food as early as four days after birth, initially licking particles of food from their mother's mouths. This process apparently allows them to quickly identify edible leaves, and young sloths typically have the same preferences for leaf types as their mothers.
Brown-throated sloths have lived for at least three years in captivity.
Classification
There are seven recognised subspecies of the brown-throated sloth, although these are not all readily distinguishable:- Bradypus variegatus boliviensis, GrayJohn Edward GrayJohn 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 ....
1871 - Bradypus variegatus brasiliensis, BlainvilleHenri Marie Ducrotay de BlainvilleHenri Marie Ducrotay de Blainville was a French zoologist and anatomist.Blainville was born at Arques, near Dieppe. In about 1796 he went to Paris to study painting, but he ultimately devoted himself to natural history, and attracted the attention of Georges Cuvier, for whom he occasionally...
1840 - Bradypus variegatus ephippiger, Philippi 1870
- Bradypus variegatus gorgon, ThomasOldfield ThomasOldfield Thomas FRS was a British zoologist.Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and sub-species for the first time. He was appointed to the Museum Secretary's office in 1876, transferring to the Zoological Department in 1878...
1827 - Bradypus variegatus infuscatus, WaglerJohann Georg WaglerJohann Georg Wagler was a German herpetologist.Wagler was assistant to Johann Baptist von Spix, and became Director of the Zoological Museum at the University of Munich after Spix's death in 1826...
1831 - Bradypus variegatus trivittatus, CornaliaEmilio CornaliaEmilio Cornalia was an Italian naturalist. He was born in Milan and died in the same city.He was conservator from 1851 to 1866, and director from 1866 till his death, of the Milan Museum of Natural History, and was interested in all areas of biology.He was one of the group of leading scientists...
1849 - Bradypus variegatus variegatus, SchinzHeinrich Rudolf SchinzHeinrich Rudolf Schinz was a Swiss physician and naturalist.Schinz was born at Zurich and studied medicine at Würzburg and Jena, returning to Zurich in 1798 to practice...
, 1825
The closest living relative of the species is the pale-throated sloth, which has a very similar appearance, except for the color of the fur around the throat. The two species are estimated to have diverged just 400,000 years ago, whereas their ancestors diverged from the maned sloth over 7 million years ago.