Science, Tech, Math › Animals & Nature Stegomastodon Facts Share Flipboard Email Print WolfmanSF/National Museum of Natural History/Wikimedia Commons/Public Domain Animals & Nature Dinosaurs Prehistoric Mammals Basics Paleontologists Carnivores Dinosaurs & Birds Herbivores Marine Reptiles Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated July 01, 2018 Name: Stegomastodon (Greek for "roof nippled tooth"); pronounced STEG-oh-MAST-oh-don Habitat: Plains of North and South America Historical Epoch: Late Pliocene-Modern (three million-10,000 years ago) Size and Weight: About 12 feet long and 2-3 tons Diet: Plants Distinguishing Characteristics: Moderate size; long, upward-curving tusks; complex cheek teeth About Stegomastodon Its name sounds impressive—like a cross between a Stegosaurus and a Mastodon—but you might be disappointed to learn that Stegomastodon is actually Greek for "roof-nippled tooth," and that this prehistoric elephant wasn't even a true Mastodon, being more closely related to Gomphotherium than to the genus to which all Mastodons belonged, Mammut. (We won't even mention Stegodon, another elephant family to which Stegomastodon was only distantly related.) As you may already have guessed, Stegomastodon was named after its unusually complex cheek teeth, which allowed it to eat such un-pachyderm-like foods as grass. More importantly, Stegomastodon is one of the few ancestral elephants (besides Cuvieronius) to have prospered in South America, where it survived until historical times. These two pachyderm genera made their way south during the Great American Interchange, three million years ago, when the Panamanian isthmus rose up from the seafloor and connected North and South America (and thus allowed the native fauna to migrate in both directions, with sometimes deleterious effects on native populations). To judge by the fossil evidence, Stegomastodon populated the grasslands east of the Andes mountains, while Cuvieronius preferred higher, cooler altitudes. Given that it survived until shortly after the last Ice Age, 10,000 years ago, it's almost certain that Stegomastodon was preyed on by the indigenous human tribes of South America—which, along with inexorable climate change, drove this pachyderm to complete extinction.