Giant ground sloth skeleton, 19th-century illustration. Megatherium (known as the giant ground sloth) was a large, extinct mammal that lived from the Miocene through the Pleistocene, from 2 million years ago to 10,000 years ago. It was primarily found in South America. A herbivorous mammal with long curved claws, it was as large as an elephant (up to 6 metres long) and among the largest land mammals of its time. This artwork was published in an 1864 edition of 'The World Before the Deluge' by Louis Figuier.