13,600-Year-Old Mastodon Skull Discovered in Iowa Riverbank
Mastodons once lumbered across North America. A member of the same animal family as mammoths and modern-day elephants, these ancient creatures roamed for millions of years, but died out in the end of the Pleistocene, around 10,500 years ago. Their decline coincided with several other critical changes, including the receding of the Ice Age glaciers and the spread of human beings across the continent.