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Linne’s Two-toed Sloth

Choloepus didactylus

There's slow much to love about this new face at Stone Zoo! Baby Siesta was born on June 27 and is the fourth offspring for parents Lunesta and Nero. Viewing tip: baby has darker fur than mom, which may help you glimpse a peek when you visit.

About the Linne’s Two-toed Sloth


Geographic Range:


Class: Mammalia  
Order: Xenarthra
Suborder: Folivara or Phyllophaga
Family: Megalonychidae (two-toed)
Genus: Choloepus  
Species: didactylus

The Linne’s two-toed sloth is so named because it has just two toes on its forelimbs; its rear limbs, as with all sloths, have three. Sloths are tree-dwellers who spend the majority of their time hanging upside down. True to their name, sloths lead a laid-back life, attributable to their slow metabolism. They climb only about 6 to 8 feet per minute, sleep about 15-18 hours a day, and hit the ground of their rainforest habitat only about once a week to urinate and defecate.

Sloth Facts

In size and shape, the sloth can be compared to a small dog. These tree-dwelling herbivores have relatively flat faces with a short, dark snout. Their front legs are longer than their rear legs, but all four are long and thin, making them very adept at hanging. As its name “two-toed sloth” suggests, its front limbs have--you guessed it-- two toes. However, like all species of sloths, its rear limb has three toes. All four of its feet have very calloused pads.  Sloths are also covered in two layers of thick hair. The outer layer can be about 6 inches long and provides a perfect, moist environment for the growth of many organisms. Their hair actually grows in the opposite direction of most mammals because sloths spend the majority of their lives upside-down!

They're born with a set of hollow molars used for grinding food, and these teeth have the ability to grow continuously throughout the sloth’s life. Due to sloths' flattened faces, short snouts, and lack of teeth in the front of their mouths, they use their hardened lips to grasp and tear vegetation. They have relatively poor hearing and vision, but their keen sense of smell helps them find food. Although the front legs are longer than the back, the sloth’s long, thin limbs are designed for climbing and hanging. At the end of their toes are 3- to 4-inch curved claws that are useful in climbing, gathering food, and for defense.

Weight: 6.8 to 17.6 pounds
Length: 50 to 70 centimeters

Sloths are omnivores, but eat mostly vegetation, preferring buds, tender shoots and leaves.  Extremely low rates of metabolism allow sloths to survive on relatively little food. Some research suggests that it may even take up to a month for food to fully digest!

Sloths are generally solitary and adults pair solely in order to mate. Breeding occurs year-round. The gestation period is five to six months. Mothers give birth upside-down in the trees, and babies immediately seek the shelter of her chest for protection and to begin nursing. The young nurse for one month and during that time “inherit” a preference for certain foods from their mother. This specialization of diet is thought to minimize competition with other sloths in the same forest. Babies are 10 inches in length and weigh 12 ounces when born. They cling to their mother's belly for five weeks until they have the strength to move on their own. The young leave their mother after nine months. Females reach sexual maturity in three years and males at four to five years.

Sloths receive their common name from the slow-paced lifestyle that they lead. Their average climbing speed is only 6 to 8 feet per minute. Sloths are extremely cautious. They're unable to support their own body weight in order to walk on the ground and, as a result, rarely leave the trees. They come to the ground only about once a week to urinate and defecate. When on the ground, they're forced to drag themselves forward, using their clawed forelimbs. Luckily, they're able to swim and will enter water to cross a river or to cool off. 

Primarily nocturnal, sloths sleep 15 to 18 hours a day. Their average body temperature can vary approximately 10 degrees daily.

Found in the tropical rainforests of northwestern Brazil, northern Bolivia, Ecuador, Guyana, Venezuela, Panama, Costa Rica, Nicaragua, Colombia and northern Peru.

Median Life Expectancy:
In the wild: 10 to 12 years
In captivity: about 30 years

Jaguars, ocelots and humans

Fun Facts:

  • The sloth is the world's slowest mammal
  • Sloths move so slowly that their hair is the perfect habitat for algae to grow. Algae give sloths a green tint and provides camouflage among the trees.

Committed to Conservation

Zoo New England participates in the Linne's two-toed sloth Species Survival Plan. By sharing research and knowledge, participating institutions work together to establish guidelines that best ensure the health of captive populations, and with success, the survival of otherwise extinct species.

Thanks to a collaboration between Zoo New England, San Diego Zoo, and Boston Children’s Hospital, animal-oriented stories like Nero's are broadcasting in every hospital patient room and waiting area on the San Diego Zoo Kids channel. Learn more.