Ground Sloths (Megatherium)

Megatherium was about the size of an elephant. It was roughly 20 feet (6 m) long and weighed about 3-4 tons.
Four species of ground sloths inhabited the United States at the end of the last Ice Age. These were Jefferson's ground sloth (Megalonyx jeffersonii), Laurillard's ground sloth (Eremotherium laurillardi), the Shasta ground sloth (Nothrotheriops shastensis), and Harlan's ground sloth (Glossotherium harlani). Of these four only two, Jefferson's and Harlan's ground sloths, are found in the midwestern U.S.

Ground sloths were large relatives of the modern two-toed sloths (Choloepus spp.) and three-toed sloths (Bradypus spp.). Unlike modern sloths, which spend most of their time in trees, the ground sloths spent all of their time on the ground. This is fortunate because Jefferson's and Harlan's ground sloth were each about the size of an oxen.

All four species of ground sloth had very large claws. However, all were herbivores. They had relatively small, blunt teeth, which they probably used for browsing on trees and shrubs.

The shape of their hip bones indicates that they could stand up on their hind legs. This would allow them to reach high up into trees for the best leaves and twigs.

All four species of ground sloth became extinct in North America approximately 10,000 years ago. The reason for their extinction is being studied by paleontologists.