Megatherium

Megatherium (meaning "Great Beast") was a genus of rhino-sized ground sloths endemic to North America that lived from the Pleistocene existing for approximately 5.3 million years. Its size was exceeded by only a few other land mammals, including mammals like Moeritherium and the Entelodon.

Ancestor
The rhinoceros-sized Promegatherium is suggested to be the ancestor of Megatherium.

Description and characteristics
Weighing almost a much as an elephant, Megatherium must have been one of the most impressive animals ever to walk the Earth. It was a massive ground sloth, covered in long dark hair. It had huge claws, and could walk on its hind legs rather like a bear. Megatherium was one of the largest mammals known, weighing up to eight tons, about as much as a bull African Elephant. Although it was 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 twenty feet (6 m) tall, twice the height of an elephant. This sloth, like a modern anteater, walked on the sides of its feet because its claws prevented it from putting them flat on the ground. Megatherium species were members of the abundant Pleistocene Megafauna, large mammals that lived during the Pleistocene epoch. 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.

Behavior and habitat
Megatherium is thought to have been a herbivore, although there have been suggestions that its long claws and very strong forelimbs may have allowed it to scavenge meat, or even kill animals such as glyptodonts. Fossilised footprints show that it often walked on its hind legs, although there is much debate as to what it looked like when it did. Megatherium inhabited woodland and grassland environments of the lightly wooded areas of South America.