Date: Pliocene Epoch (4-1.8 million years old)
Description: Mastodons were similar to wooly mammoths, but with several key differences. Mastodons were shorter than mammoths, with longer and more muscular bodies. Both genders had long, curving tusks, though the males’ were more massive than the females’. They had hair covering their bodies to protect them from the cold climate of glacial North America, though this hair was not as thick as the wooly mammoth’s. But the key difference is what we see in these mandibles: mastodons had special, cusp-shaped teeth. Unlike mammoths, which were grazers of low-lying vegetation, mastodons fed on tall grasses and tree leaves, using their special teeth to grind up this much tougher vegetation. These mandibles were found near Chadron, Nebraska and the extent of fossilization indicates that these are quite older than any of our mammoth fossils. Mastodons became extinct after the Ice Age 10,000 years ago.
Donor: Sioux City Academy of Science and Letters.