Three-Toed Tree Sloths: Bradypodidae

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THREE-TOED TREE SLOTHS: Bradypodidae

BROWN-THROATED THREE-TOED SLOTH (Bradypus variegatus): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

The three-toed tree sloth family consists of four species, groups within the family that share similar characteristics. All species have eighteen peg-like teeth, slim bodies, long limbs, and tiny tails. Front limbs are longer than their back limbs.

Sloths' fur ranges in color from gray to brown. The brown-throated three-toed sloth has brown fur in its throat area and may also have white or red fur. The pale-throated sloth has dark fur on its back and lighter colored fur on its front. The maned sloth has long, black hair on its back and neck. The monk sloth has a tan face.

All species of sloths may have green in their fur. This is caused by algae (AL-jee), tiny water plants growing in sloths' hair. Algae are a food source, and sloths lick their fur when hungry. Sloths live in trees, and the green and brown in their fur helps them blend in with the trees and hide from predators, animals that hunt them for food.

The head and body length of three-toed tree sloths ranges from 15.8 to 30.3 inches (40 to 77 centimeters). Tail length ranges from 1.9 to 3.5 inches (4.7 to 9 centimeters). They weigh from 5.1 to 12.1 pounds (2.3 to 5.5 kilograms). The monk sloth is about 20 percent smaller than other sloth species.

Three-toed tree sloths have three long, hooked claws on the digits (toes) of each foot. Sloths use the claws measuring from 3.2 to 3.9 inches (8 to 10 centimeters) to hang upside down from tree branches. Sloths can see a great distance because sloths can turn their heads 270°. They can turn so far because sloths have eight or nine neck vertebrae (bone segments)—most mammals, including humans, have seven vertebrae.

GEOGRAPHIC RANGE

Three-toed tree sloths live in Central and South America. Species are found in Mexico, Argentina, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, Honduras, Nicaragua, Panama, Paraguay, Suriname, Venezuela, French Guiana, and Guyana. Monk sloths live only on Escudo de Veraguas Island off the coast of Panama.

HABITAT

Three-toed sloths live primarily in forests. They are located in rainforests, where heavy rain throughout the year produces abundant growth. Some species also live in dry forests and coniferous forests where leaves are green year-round. In addition, sloths have been found living in trees in parks and pastures.

DIET

Three-toed sloths are herbivores and eat the leaves and shoots of trees. Sloths move slowly because their diet of leaves produces little energy. To make up for the lack of energy, sloths have a low body temperature of 86° to 90°F (30° to 34°C).

BEHAVIOR AND REPRODUCTION

Three-toed sloths live upside down. They sleep, mate, and give birth in that position. Sloths are solitary. They are also polygynous (puh-LIH-juh-nus), meaning that males mate with more than one female. Sloths breed at any time during the year. The male leaves after mating, and the female bears usually one young within five to six months. She carries this offspring with her for up to a year. During this time, the young sloth develops a taste for the leaves on which its mother feeds.

FOURTH SLOTH SPECIES FOUND ON ISLAND

The identification of a new three-toed tree sloth species in 2001 was a living lesson in evolution. The monk sloth is also known as the pygmy sloth because it is 20 percent smaller than the three other Bradypus species. The new species lives only on Escudo de Veraguas Island, part of the Boca del Toro islands located off the east coast of Panama. Monk sloths live in red mangrove trees and are thought to be polygynous.

Three-toed sloths are active during the day and night. During the day, they position themselves in trees so that the sun warms them. They sleep as much as eighteen hours each day.

Sloths use their claws as hooks to move through trees. They move slowly and travel at most 125 feet (38 meters) in a day. Their on-ground speed is 15 yards (13.7 meters) per minute. In the water, three-toed sloths swim well. Sloths also use their claws as a defense against predators like hawks, harpy eagles, boa constrictors, and anacondas, a type of snake.

THREE-TOED TREE SLOTHS AND PEOPLE

Three-toed sloths can be important to medical research because they heal quickly and do not get infections easily. Scientists are interested to know why this is.

CONSERVATION STATUS

The maned sloth is ranked as Endangered by the World Conservation Union (IUCN). This species faces threats of becoming extinct in the future because habitat is lost as trees are cut down in forests. Hunting also reduces the population.

BROWN-THROATED THREE-TOED SLOTH (Bradypus variegatus): SPECIES ACCOUNT

Physical characteristics: The brown-throated three-toed sloth is named for the brown fur around its throat. Chest fur is also brown, and adult males have a patch of yellow or orange fur on their backs between their shoulder blades. On this patch are thin stripes of black fur. These tree sloths have dark fur "masks" around their eyes and the area where fur covers their ears.

Other fur color varies, depending on where the sloths live and mate. Just as human parents pass along traits like eye color to their children, sloth offspring inherit the coloring of their parents. Brown-throated sloths may have grayish brown or reddish brown hair. While some have patches of white hair in their fur, other sloths are almost completely white.

These sloths range in length from 1.5 to 2 feet (45 to 60 centimeters) and weigh from 7 to 11 pounds (3 to 5 kilograms). They have tiny tails and three digits with claws on each of their four feet.

Geographic range: Brown-throated tree sloths live in Mexico, throughout Central America, and in parts of South America. They are found in Argentina, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, Honduras, Nicaragua, Panama, and Paraguay.

Habitat: Brown-throated sloths adapt to a variety of habitats. They live in rainforests, evergreen forests, parks, and pastures. They may spend up to three days in a tree before moving to another tree.

Diet: Since people frequently saw brown-throated sloths in Cecropia (sih-KROPE-ee-uh) trees, it was thought that sloths only fed on these trees. However, the tree-toed sloths eat leaves and twigs from up to thirty different species of trees. Since the sloth learns feeding habits from its mother, it prefers to eat from the same type of tree that its mother does.

Behavior and reproduction: Three-toed sloths are also known as ai by the Guarani people of South America. The name comes from the noise made when sloths are in trouble—they make a whistling sound and hiss.

Brown-throated sloths are solitary except while they're breeding. Once they mate, the male leaves. The female gives birth in five to six months. The female typically has one young. However, there have been a few cases of twin births. At birth, a sloth weighs from 0.4 to 0.6 pounds (0.2 to 0.25 kilograms).

The mother sloth carries her baby on her stomach. The offspring nurses for about six weeks. After that, it feeds itself by reaching up for food in the trees where its mother lives. The young sloth also learns its range, the area where it will travel to live and feed. By the age of six months, the sloth keeps one foot on its mother while reaching for food. After about nine months, the mother leaves her offspring to live on its own.

Brown-throated three-toed sloths and people: Sloths are of interest to medical researchers because they heal quickly. The brown-throated sloths have also been hunted as food.

Conservation status: Brown-throated sloths are not threatened. ∎