Glyptodont << GLIHP tuh dont >> is the name for a prehistoric group of giant armadillo-like animals. The word glyptodont means grooved tooth. Each tooth of these animals had three lobes, or sections, separated by a deep groove on the sides. Glyptodonts flourished in South America, where they originated about 40 million years ago. They are also known from fossils found in Central and North America. About 4 million years ago, a land connection formed between North and South America. Species that had evolved on one continent could expand their populations to the other.
Glyptodonts had a massive shell, or carapace, that covered the top and sides of its body. The shell consisted of more than a thousand bony plates, called osteoderms, joined tightly at the edges. The top of the head also had a protective cover of bony plates. The tail had very thick rings of bony plates. All these helped provide protection from predators. Doedicurus, the largest of the many glyptodont lineages in South America, had huge spines on the tail for additional protection. Fur covered the belly, neck, chin, and cheeks. Although they resembled tortoises, glyptodonts were mammals, not reptiles.
Glyptodonts fed on plants and probably ate constantly to support their enormous bulk. Adults weighed about a ton (0.9 metric ton) or more and were about 10 feet (3 meters) long. Glyptodonts were slow and could not outrun their predators. But few predators were strong enough to prey on glyptodonts. One genus, Glyptotherium, successfully invaded North America. There they faced larger predators, such as saber-toothed cats, which sometimes preyed on young glyptodonts. Glyptotherium eventually occupied tropical and subtropical habitats near lakes and rivers from Central America to the southern United States. See Great American interchange.
Glyptodonts became extinct about 11,500 years ago at the end of the Ice Age. Prehistoric people may have hunted glyptodonts for food. In one case, early people in South America used a glyptodont carapace for shelter. Some experts think that overhunting drove glyptodonts and many other large Ice Age animals into extinction. Others think that climate change was mainly responsible for the extinctions.
