Megatherium was a gigantic ground sloth, among the largest mammals to ever live, possibly the largest. It was around the weight of an African bull elephant, 5 tons, and standing on its hind legs, was 20 ft tall. Although an herbivore, Megatherium possessed huge sharp claws it could have used to stab predators in its defense. Megatherium was so large that it had no predators in its ecological niche, being too large to take down. In Latin, megatherium means "giant beast".
Megatherium lived from 2 million to 8,000 years ago, when it died out during the Pleistocene extinction, which was either caused by human hunting, an asteroid impact, or a combination of both. Its relatively recent death raises the possibility that one day we will be able to recover its intact genetic material and revive it. Megatherium belongs to a category of animal, the ground sloths, which were numerous in prehistoric times but quite extinct today. It is thought that the last ground sloths may have died out as recently as 1550 in Hispaniola and Cuba. They were all large herbivores, but Megatherium was the largest.
Megatherium is one among the Pleistocene megafauna, which included giant cats, lizards, bears, wolves, and even kangaroos. These megafauna lived all over the world, although Megatherium's range was limited to the Americas. Living in the last land masses to be colonized by human settlers, Megatherium would have been able to avoid hunting parties. It must have been a daunting task for a group of humans to take down a Megatherium, though - numerous poisoned arrows were probably required. The meat from such an animal could probably have fed hundreds, however.
Fossil prints from Megatherium suggest that it spent a great deal of time walking on its hind legs, although there is much controversy over how it would have looked as it did this. Its claws were so huge that it would have needed to walk on them sideways, like an anteater.