Two-toed sloths spend nearly their entire lives upside-down in trees, even giving birth upside down. In fact, sloths typically come down to ground level just once a week to relieve themselves.

Slow and Steady

While sloths are known for their slow, “lazy” nature, the biological reasons for their slow motion lifestyle are quite interesting. Because sloths have a very low metabolic rate (only 40–45 percent of the expected rate for their size), they are able to eat foods that are easy to find but low in nutrients. Bacteria that are able to break down cellulose reside in their multi-chambered stomachs. Sloths’ slow metabolisms require them to use energy sparingly, and their muscles are smaller and weaker than expected for their body size. They are also capable of regulating their body temperature. It can range from 86–93 degrees Fahrenheit—the lowest and most variable of any mammal.


Tropical lowland and montane forests of Central and South America


These herbivores eat fruit, leaves, and twigs.


  • Length: 2 feet
  • Weight: 8–19 pounds