When you think about prehistoric elephants, it's easy to confuse the mammoth (left) and the mastodon (right). After all, they roamed the world at the same time, and went extinct after the emergence of man, but before we kept detailed records (besides cave paintings). To look at them, you'd think that the mastodon would be the closer relative to modern elephants, but you'd be wrong. The two modern elephant species belong to the same family (Elephantidae) as the mammoth, but a mastodon is of the Mammutidae family. The mammoth and mastodon both belong in the order Proboscidea. Mental_floss takes you through the many differences between mammoths and mastodons, so you won't ever confuse them again.
(Image credit: Dantheman9758)