From Wikipedia
Megatherium ("Great Beast") was a genus of elephant-sized ground sloths that lived from two million to 8,000 years ago. A related genus was Nothrotheriops, which were primarily bear-sized ground sloths.
Unlike its living relatives, the tree sloths, Megatherium was one of the largest mammals to walk the Earth, weighing five tons, about as much as an African bull elephant. Although primarily a quadruped, its footprints show that it was capable of assuming a bipedal stance. When it stood on its hind legs, it was about twice the height of an elephant, or about twenty feet tall.
Megatherium had a robust skeleton with a large pelvic girdle and a broad muscular tail. Its large size enabled it to feed at heights unreachable by other contemporary herbivores. Rising on its powerful hind legs and using its tail to form a tripod, Megatherium could support its massive body weight while using the curved claws on its long forelegs to pull down branches with the choicest leaves. Its jaw is believed to have housed a long tongue, which it would then use to pull leaves into its mouth, similar to the modern tree sloth.
