Three-toed sloth
Overview
The three-toed sloths are tree-living mammals from South
South 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...

 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...

. They are the only members of the genus
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...

 Bradypus and the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Bradypodidae. There are four living species of three-toed sloths. These are the Brown-throated Sloth, the Maned Sloth, the Pale-throated Sloth, and the Pygmy Three-toed Sloth
Pygmy Three-toed Sloth
The Pygmy Three-toed Sloth is a three-toed sloth. It is endemic to Isla Escudo de Veraguas, an island off the coast of Panama, which separated from the mainland nearly 8900 years ago. The species is thought to have originated from isolation of individuals from the mainland population of Bradypus...

.

Although similar to the somewhat larger and generally faster moving two-toed sloth
Two-toed sloth
Choloepus is a genus of mammals of Central and South America, within the family Megalonychidae consisting of two-toed sloths. There are only two species of Choloepus : Linnaeus's Two-toed Sloth and Hoffmann's Two-toed Sloth...

s, the two genera
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...

 are not particularly closely related.
Encyclopedia
The three-toed sloths are tree-living mammals from South
South 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...

 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...

. They are the only members of the genus
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...

 Bradypus and the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Bradypodidae. There are four living species of three-toed sloths. These are the Brown-throated Sloth, the Maned Sloth, the Pale-throated Sloth, and the Pygmy Three-toed Sloth
Pygmy Three-toed Sloth
The Pygmy Three-toed Sloth is a three-toed sloth. It is endemic to Isla Escudo de Veraguas, an island off the coast of Panama, which separated from the mainland nearly 8900 years ago. The species is thought to have originated from isolation of individuals from the mainland population of Bradypus...

.

Although similar to the somewhat larger and generally faster moving two-toed sloth
Two-toed sloth
Choloepus is a genus of mammals of Central and South America, within the family Megalonychidae consisting of two-toed sloths. There are only two species of Choloepus : Linnaeus's Two-toed Sloth and Hoffmann's Two-toed Sloth...

s, the two genera
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...

 are not particularly closely related. Recent phylogenetic analyses support the morphological data from the 1970s and 1980s that the two genera are not closely related and that each adopted their arboreal lifestyles independently. It is unclear what ground-dwelling sloth taxa the three-toed sloths evolved from; the two-toed sloths appear to nest phylogenetically within one of the divisions of Caribbean megalonychids, and thus probably either descended from them or are part of a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 that invaded the Caribbean multiple times. Both types of sloth
Sloth
Sloths are the six species of medium-sized mammals belonging to the families Megalonychidae and Bradypodidae , part of the order Pilosa and therefore related to armadillos and anteaters, which sport a similar set of specialized claws.They are arboreal residents of the jungles of Central and South...

 tend to occupy the same forests: in most areas, a particular single species of three-toed sloths and a single species of the larger two-toed type will jointly predominate. Famously slow-moving, the sloth travels at a top speed of 0.24 kilometre per hour (0.149129086256263 mph).

Although they are quite slow in trees, three-toed sloths are agile swimmers. The offspring cling to their mother's bellies for around 9 months or so. They cannot walk on all four limbs, and so they must use their front arms and claws to drag themselves across the rain forest floor. They do not have a mating season and breed year round.

The three-toed sloth is arboreal (tree-dwelling), with a body adapted to hang by its limbs. It lives high in the canopy but descends once a week to defecate on the forest floor. Its long, coarse, grayish-brown fur often appears greenish, not due to pigment but to algae growing on it. The sloth’s greenish color and its sluggish habits provide an effective camouflage: hanging quietly, the sloth resembles a bundle of leaves. Large curved claws help the sloth to keep a strong grip on tree branches.

Characteristics

Three-toed sloths are about the size of a small dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

 or a large cat, with the head and body having a combined length of around 45 centimetres (18 in), and the animal having a weight of 3.5–4.5 kg (7.7–9.9 ). Unlike the two-toed sloths, they also have a short tail of 6–7 cm (2.4–2.8 ), and they have three clawed toes on each limb. They are frequently referred to as three-toed sloths, however all sloths have 3 toes, the difference is found in the number of fingers; meaning they are now more appropriately referred to as three-fingered sloths. This idea was first implemented by Judy Avey-Arroyo, co-founder of the worlds only sloth sanctuary, but is now recognized in numerous publications as the correct terminology for these animals. They move between different trees up to four times a day, although they prefer to keep to a particular type of tree, which varies between individuals, perhaps as a means of allowing multiple sloths to occupy overlapping home ranges without competing with each other. Three-toed sloths have no incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...

 or canine teeth, just a set of peg-shaped cheek teeth that are not clearly divided into premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...

s and molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....

s, and lack homology with those teeth in other mammals and are thus referred to as molariforms. The molariform dentition in three-toed sloths is simple and can be characterized as dental formula
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...

 of:

The three-toed sloth, unlike most other mammals, does not fully maintain a constant body temperature, and this limits it to warm environments.

Members of this species tend to live around 25 to 30 years, reaching sexual maturation at 2 years of age.

Females give birth to a single young after a gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....

 period of around six months. They are weaned
Weaning
Weaning is the process of gradually introducing a mammal infant, either human or animal, to what will be its adult diet and withdrawing the supply of its mother's milk.The process takes place only in mammals, as only mammals produce milk...

 at about 9 months of age, at which point, the mother leaves her home territory to her offspring and moves elsewhere. Adults are solitary, and mark their territories using anal scent gland
Scent gland
Scent glands are found in the genital area of most mammals and in various other parts of the body, such as the underarms of humans and the preorbital glands of deer and muskox. They produce a semi-viscous fluid which contains pheromones. These odor-messengers indicate information such as status,...

s and dung middens.

Species

  • Bradypus pygmaeusPygmy Three-toed Sloth
    Pygmy Three-toed Sloth
    The Pygmy Three-toed Sloth is a three-toed sloth. It is endemic to Isla Escudo de Veraguas, an island off the coast of Panama, which separated from the mainland nearly 8900 years ago. The species is thought to have originated from isolation of individuals from the mainland population of Bradypus...

  • Bradypus torquatusManed Three-toed Sloth
    Maned Three-toed Sloth
    The maned sloth , also known as the ai , is a three-toed sloth that lives only in Brazil. It is one of only four species of three-toed sloth.-Distribution and habitat:...

  • Bradypus tridactylusPale-throated Three-toed Sloth
    Pale-throated Three-toed Sloth
    The Pale-throated sloth is a species of three-toed sloth that inhabits tropical rainforests in northern South America. It is similar in appearance to, and often confused with, the brown-throated sloth, which has a much wider distribution...

  • Bradypus variegatusBrown-throated Three-toed Sloth
    Brown-throated Three-toed Sloth
    The brown-throated sloth 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.-Description:...


External links

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