Sloths are fascinating animals that live in rainforests in central and south america. There are two families of sloths; two toed and three toed. Within the the families there are three species each. Some sloths are nocturnal(awake at night) and some are diurnal(awake in the day) Sloths are about the size of a medium sized dog and live 20-30 years.
Sloths evolved from the ancient Xenarthra from 40 million years ago. Other animals like anteaters and armadillos also evolved from Xenarthra. Ancient sloths didn't live in trees, they lived on land and were the size of bears. The Megatherium, another species of sloths,were larger than an elephants. Extinct species of sloths like as Megatherium americanum and Eremotherium eomigrans weighed up to 5 tonnes.