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Hoffman's Two-Toed Sloth

two-toed sloth pic
Scientific Name:
Choloepus hoffmanni

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order:Xenarthra

Family:Megalonychidae

Distribution: Hoffman’s two-toed sloth is found in South and Central American countries including: Bolivia, Brazil, Colombia, Ecuador, Guyana, Nicaragua, Panama, Peru, and Venezuela. They are most prevalent in the Amazon Rainforest Basin of central Brazil and Peru.

Habitat: Almost entirely arboreal (tree-dwelling) creatures, two-toed sloths live high in the forest canopy of tropical rainforests. They can be found resting in the crowns of trees or the lianas (woody climbing vines) that are interwoven throughout the canopy treetops. Although nearly all of their normal activity occurs hanging upside down, two-toed sloths will descend to the ground for urination and defecation, or to change trees to find a new food source.

Description: Hoffman’s two-toed sloths range in body length from 21 to 29 inches, and range in weight from 9 to 20 pounds. They get their name from having two large claws on their forelimbs that can measure up to 3 inches in length. Two-toed sloths also have the lowest and most variable body temperature and the lowest muscle mass relative to overall body weight of any mammal. Their fur is brown in color, ranging from light tan to dark brown, with lighter fur around their face and head. Their average lifespan is 10-12 years in the wild, but they can live up to 31 years in captivity.

Diet: The Hoffman’s two-toed sloth is mainly an herbivore that eats mostly leaves, but can also consume animal matter such as bird eggs, nestlings, lizards, and insects. At the Como Zoo, the sloths are on a diet consisting of lettuce and carrots. The sloths have large, multi-chambered stomachs similar to a cow’s that are tolerant of the toxic chemicals contained in the foliage that they eat. Having an extremely slow metabolism, Hoffman’s two-toed sloths can take up to a week to digest a meal; they only need to descend from the trees once every 5-7 days to urinate and defecate. 

Behavior: Sloths are unique animals that spend nearly all their time upside down hanging in a tree; they even eat, sleep and give birth upside down! They spend so much time upside down that their internal organs have actually been repositioned over time. They are known for their speed, or lack there off, because they only move between 6 to 8 feet a minute. They may look clumsy, but are surprisingly good swimmers. The ability to swim is very helpful for crossing streams or even rivers that are common in their wet habitat. On land they are not as agile. In fact, their limbs are not strong enough to support them and they have to drag themselves on their bellies to get around. Sloths live most of their lives in solitary, only meeting up to mate. Females have been known to congregate in small groups, but males are almost always found alone.  Sloths are usually not territorial, but they can be if their young is threatened.

Breeding: Female two-toed sloths reach sexual maturity when they are around 3 years old. It takes a little longer for the males, who generally reach sexual maturity around 4 or 5 years of age. Sloths give birth to one child at a time. Their gestation period (the time between fertilization and birth) tends to be between 7-10 months. The relatively long gestation period allows the young to be fairly developed when they are born. Once the baby is born the mother’s work isn’t finished. The baby sloth clings to its mother’s fur for the next 6-9 months, after which the baby sloth ventures off on its own. The babies don’t go too far, and keep a tight association with their mother’s until they are around the age of 2. The average time between pregnancies is between 14-16 months. The sloths have no defined mating season, and mating seems to occur at random times.

Adaptations: Although sloths are mammals, they are heterothermic. This means that they have a very low variable body temperature that greatly depends on the environment. Their body temperature ranges from 86-930 F, which is cold compared to most mammalian standards. By keeping their body temperature low, they are able to conserve energy that would otherwise be used to maintain a higher body temperature.

The sloths also conserve energy by having incredibly low muscle mass. Only 25% of a sloth’s body is made of muscle, which is especially interesting when compared to other mammals that have twice that amount.

A sloth’s fur has special grooves specially made to house algae. The moist air of their habitat, as well as their lack of movement and specialized fur that allows algae to grow within the hair shaft, are perfect conditions to form a symbiotic relationship between the two-toed sloths and the algae. The greenish color given off by the algae provides camouflage for the sloth, and the sloth provides a home for the algae. The way their hair falls is also an adaptation. Because they spend the majority of their lives hanging upside down in trees, their hair is parted along their stomachs and flows from belly to back so that rainwater will run off.

Conservation: Sloths are not on the endangered species list. However, their habitat is quickly being destroyed, leaving them homeless and vulnerable to a decrease in their population size.

Miscellaneous:

 

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MORE ON THE EVOLUTIONARY HISTORY OF HOFFMAN'S TWO-TOED SLOTH

Sources:

http://animaldiversity.ummz.umich.edu/site/accounts/information/Choloepus_hoffmanni.html

http://animals.nationalgeographic.com/animals/mammals/two-toed-sloth.html

http://bristolzoo.org.uk/learning/animals/mammals/two-toed-sloth

http://www.britannica.com/eb/article-218683/sloth

Gould, Edwin; McKay, George. “Sloths” Encyclopedia of Mammals. Ed. Edwin Gould, George McKay.  1 vol. 2nd edition. Weldon Owen Pty Limited. San Francisco. 1998.

http://www.tigerhomes.org/animal/tow-toed-sloth.cfm

http://xenarthra.org