Giant Sloths

Hapalops was an early ground sloth, appearing in the early Miocene Epoch in South America. It was small in comparison to some of the later ground sloths, only three feet (one meter) in length. Because of its small size, long legs and sharp-clawed feet, it may have spent some of its time in trees.

Megatherium is the largest known ground sloth, reaching 20 feet (six meters) in length and weighing as much as three tons (13,200 kilograms). Megatherium was named by Sir Richard Owen in 1856.

One of the paleontologically best-known ground sloths is Glossotherium, which reached 13 feet (four meters) in length. Glossotherium travelled northward from South America throughout North America about three million years ago during the Pliocene Epoch. Coprolites from Glossotherium indicate that it liked to feed on desert shrubs. Many specimens of Glossotherium have been found in the Rancho La Brea Tar Pits in Los Angeles, California.

Megalonyx was the most widespread of the North American ground sloths, reaching all parts of North America except the far north-east. It was probably a very hardy animal, as its fossils have been found at high altitudes. Megalonyx was about the size of a modern cow, and it showed a lot of variation in its morphology. Many species have been assigned to the Megalonyx genus, but probably truly represent only a few species.

Why did all of the ground sloths go extinct about 10,000 years ago? It has been suggested that competition with other North American herbivores and predation by carnivores such as sabre-toothed cats and dire wolves, or hunting by humans might have caused their extinction, as many of the South American ground sloths survived until after the last Ice Age.

Be sure to visit my web site for more links to Natural History Museums.

Go To Page: 1 2

Articles in this Topic    Discussions in this Topic