5 Ice Age Creatures You Never Knew Existed

When it comes to the Ice Age, our imaginations often wander to the mighty mammoths of Siberia or to the kooky cartoon companions of Ray Romano. However, the great giants of the last glacial period were as diverse as they were captivating.

Though the name "Ground Sloth" refers to a diverse suborder of mammals from the last glacial period, one of this group's most distinctive is Megatherium. These South American herbivores were drastically different from their contemporary cousins; they were tertiary beasts with thick skin, giant claws and long tails for protection against predators. They could grow up to 20 feet, larger than many contemporary elephants.

The other woolly wonder of the Ice Age was the woolly rhino, which dwelled in the same habitat as the mammoths that so often overshadow them. Their lack of notoriety might be in part because of their early extinction. While mammoths lived up to 2,000 B.C. in a small isolated community on Wrangel Island, most predictions peg the woolly rhino's extinction at 8,000 B.C., making their fossil record harder to trace.

One of the oldest great mammals to go extinct during the final glacial period was the Glyptodon. These relatives of modern day armadillos were massive, reaching up to 10 feet at their peak. During the Ice Age, these creatures lived in the damp swamps of Arizona, but as the swamps dried up in the warming climate and hunters began to target the animals for their valuable shells, they gradually went extinct.

Not to be confused with their Eurasian relatives, the American mastodon was a forest dweller rather than a grassland grazer. Shorter, longer and more muscled than the mammoth, these giants of the Ice Age more closely resembled current Asian elephants. Their extinction coincides directly with the arrival of humans in the Americas and many fossils indicate that hunters carved their bones into weapons.

The average European cave bear was the size of the largest modern brown bears (weighing between 800 and 1,100 pounds) and one of the few Ice Age giants not believed to have been hunted to extinction by humans. The lack of cave paintings of these creatures might indicate that humans avoided them purposefully. They went extinct long before many of the other large animals of the Ice Age, but the cause of their extinction remains controversial. The most viable hypothesis claims that the bears gradually went extinct as the plants on which they fed slowly diminished.