Linnaeus's two-toed sloth (''Choloepus didactylus''), also known as the southern two-toed sloth, unau, or Linne's two-toed sloth is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sloth Sloths are a Neotropical realm, Neotropical group of xenarthran mammals constituting the suborder Folivora, including the extant Arboreal locomotion, arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of move ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

, found in

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

, and

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

north of the Amazon River. There is now evidence suggesting the species' range expands into

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

. It's the largest

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

sloth species.

Description

Males and females are the same size, growing to lengths of approximately 53 to 89 cm (21 to 35 in), not including the length of the tail, and weigh approximately 4 to 11 kg (9 to 24 lb). Their fur color ranges from a brownish yellow to a pale tone of brown, however, in the wild their fur sometimes has a green hue from algae that grows on their fur during the rainy season. Their belly fur is slightly lighter in color than the body and they have no undercoat. The belly hair is parted along the midline and flows towards the animals back (spine), the opposite direction that fur flows on most other mammals. Young sloths tend to have softer and darker fur than adults.

Phylogeny

Sloths belong to the order

Pilosa The Order (biology), order Pilosa is a clade of xenarthran placental mammals, native to the Americas. It includes anteaters and sloths (which include the extinct ground sloths). The name comes from the Latin word for "hairy". Origins and taxon ...

, which also includes

anteater Anteaters are the four extant mammal species in the suborder Vermilingua (meaning "worm tongue"), commonly known for eating ants and termites. The individual species have other names in English and other languages. Together with sloths, they ar ...

s. They belong to the super order

Xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a superorder and major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and ...

, which includes the

Cingulata Cingulata, part of the superorder Xenarthra, is an order of armored New World placental mammals. The armadillos, whose species are split between the families Dasypodidae and Chlamyphoridae, are the only surviving members of the order. Two grou ...

. Xenarthra are edentate or toothless. They lack

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

s and have a large reduction in number of teeth with only four to five sets remaining including canines. Modern sloths are divided into two families based on the number of toes on their front feet, Choloepodidae and Bradypodidae. Linnaeus's two-toed sloth and

Hoffmann's two-toed sloth The Hoffmann's two-toed sloth (''Choloepus hoffmanni''), also known as the northern two-toed sloth, is a species of sloth from Central and South America. It is a solitary, largely nocturnal and arboreal animal, found in mature and secondary ra ...

(''

Choloepus hoffmanni The Hoffmann's two-toed sloth (''Choloepus hoffmanni''), also known as the northern two-toed sloth, is a species of sloth from Central and South America. It is a solitary, largely nocturnal and arboreal animal, found in mature and secondary rai ...

'') belong to the family Choloepodidae, which included extinct ground sloths.

Morphology

''Choloepus didactylus'' are larger than three-toed sloths. They have longer hair, bigger eyes, and their back and front legs are more equal in length. Their ears, hind feet and head are generally larger than Bradypodidae. They do however have a shorter tail. Their shoulder height, the height from the shoulder blade to the tips of the claw is longer than three-toed sloths, indicating longer arms. The species has relatively few teeth; it has four to five sets including canines and lacks

s. Molars are indistinguishable from premolars. The teeth are rootless and lack enamel, consisting only of two layers ever-growing

dentin Dentin ( ) (American English) or dentine ( or ) (British English) () is a calcified tissue (biology), tissue of the body and, along with tooth enamel, enamel, cementum, and pulp (tooth), pulp, is one of the four major components of teeth. It i ...

. Supernumerary teeth have occasionally been observed, but this has been reported in almost all mammalian orders.

Ecology

''C. didactylus'' is a solitary,

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

and

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

animal, found in

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

s. The two-toed sloth falls prey to wild cats such as the

ocelot The ocelot (''Leopardus pardalis'') is a medium-sized spotted Felidae, wild cat that reaches at the shoulders and weighs between on average. It is native to the southwestern United States, Mexico, Central America, Central and South America, ...

and

jaguar The jaguar (''Panthera onca'') is a large felidae, cat species and the only extant taxon, living member of the genus ''Panthera'' that is native to the Americas. With a body length of up to and a weight of up to , it is the biggest cat spe ...

as well as large birds of prey such as the

harpy In Greek and Roman mythology, a harpy (plural harpies, , ; ) is a half-human and half-bird mythical creature, often believed to be a personification of storm winds. They feature in Homeric poems. Descriptions Harpies were generally depict ...

and crested eagles. Predation mainly occurs when the sloth descends to the ground in order to defecate or change trees. Anacondas have also been known to hunt sloths. It is able to swim, making it possible to cross rivers and creeks, but maybe also making it more available to a predator like an anaconda. Two-toed sloths live in ever-wet tropical rainforests that are hot and humid. They tend to live in areas where there is a lot of

vine A vine is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas, or runners. The word ''vine'' can also refer to such stems or runners themselves, for instance, when used in wicker work.Jackson; Benjamin; Da ...

growth so they can easily travel from tree to tree in the canopies of the forests. They mainly eat leaves, but there is lacking data on the extent of their diet due to their nocturnal lifestyle and camouflage. ''C. didactylus'', similar to other sloth species, have a low rate of metabolism, food intake, and defecation, despite their relatively large body mass and their high volumes of

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

production. They retain their digested material for long periods of time, due to a combination of their low defecation rates and large digestive systems. This long digestion period appears to cause the sloths’ high volumes of methane production, more than most other, similar herbivores. These high methane levels may also be the result of high

formate Formate (IUPAC name: methanoate) is the conjugate base of formic acid. Formate is an anion () or its derivatives such as ester of formic acid. The salts and esters are generally colorless. Fundamentals When dissolved in water, formic acid co ...

levels in their digested material.

References

Gallery

Image:Zweizehenfaultier.png, 1883 painting Image:Choloepus didactylus - Buffalo Zoo.jpg, ''Choelopus didactylus'' at Buffalo Zoo Image:Sloth & baby, caught on Amazon. Leticia, Colombia1969.jpg, Sloth & baby, caught at Leticia,