Megatherium: Giant Ground Sloth

Megatherium was a gigantic ground sloth that lived from two million to eight thousand years ago during the Pleistocene Epoch of the Cenozoic. It weighed as much as an African elephant and when standing upright was nearly fifteen feet tall. Although the majority of ground sloths were found in the South American Pleistocene, a

Megatherium was one of the largest mammals ever to walk the earth, among others like indricotherium and deinotherium. It had thick bones and giant, club-like limbs that were undoubtedly extremely powerful. Megatherium had huge claws on its feet, much like tree sloths today. However, instead of using the claws like a modern tree sloth to anchor its body to a branch for feeding, these huge ground sloths used their claws to pull down branches to reach leaves. Due to the length of the claws, megatherium could not walk on the bottoms of its feet, but instead had to walk on the sides of its feet. Modern anteaters display this characteristic today.

The nutritional intake of the megatherium is a point of debate among scientists. Although modern sloths are vegetarian, it is quite possible that megatherium was in fact an omnivore, supplementing a mainly vegetarian diet with meat. Its teeth were poorly designed to grind up vegetation, but were triangular and better suited for chopping and slicing. Upturned fossilized remains of the giant armadillo relatives, glyptodont have suggested that megatherium might have preyed on these herbivores. Since glyptodonts weighed over a ton when full-grown, megatherium was the only animal alive in South America during the Pleistocene that could have tipped over these tank-like browsers. In any case, megatherium were not bothered by predators around at the time, not even the well-known saber-toothed cat, smilodon. Although these predators were larger than lions, they could not touch a five-ton sloth that could deliver fatal blows with its gigantic limbs.

It is not clear how megatherium became extinct, but the joining of North and South America at the Isthmus of Panama during the Pleistocene might have contributed to their demise. This land bride would eventually allow human beings to migrate southward from Beringia, where they followed herds of big game in small groups of hunter-gatherers. It is likely that early humans would have attacked megatheria for food. Also, the cyclical glaciation of the Earth during the Pleistocene might have affected the megatherium's food supply, further endangering it. By the time mankind was beginning to develop agriculture in the Middle East, megatherium had gone extinct in the Americas.