Science, Tech, Math › Animals & Nature The Dinosaurs and Prehistoric Animals of Minnesota Share Flipboard Email Print Animals & Nature Dinosaurs Basics Paleontologists Carnivores Dinosaurs & Birds Herbivores Marine Reptiles Prehistoric Mammals Amphibians Birds Habitat Profiles Mammals Reptiles 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 April 20, 2017 01 of 04 Which Dinosaurs and Prehistoric Animals Lived in Minnesota? Wikimedia Commons For much of the Paleozoic, Mesozoic and Cenozoic Eras, the state of Minnesota was underwater--which explains the many small marine organisms dating from the Cambrian and Ordovician periods, and the relative paucity of fossils that have preserved from the age of dinosaurs. On the following slides, you'll discover the most important dinosaurs and prehistoric animals discovered in Minnesota. (See a list of dinosaurs and prehistoric animals discovered in each U.S. state.) 02 of 04 Duck-Billed Dinosaurs Olorotitan, a duck-billed dinosaur of the type that has been discovered in Minnesota. Dmitry Bogdanov Despite its proximity to dinosaur-rich states like South Dakota and Nebraska, very few dinosaur fossils have been discovered in Minnesota. To date, researchers have found only the scattered, fragmented bones of an unidentified genus of hadrosaur, or duck-billed dinosaur, that probably wandered over from further west. (Of course, wherever hadrosaurs lived, there were certainly raptors and tyrannosaurs as well, but paleontologists have yet to adduce any direct fossil evidence--with the exception of what appears to be a raptor claw, discovered in the summer of 2015). 03 of 04 Various Megafauna Mammals The American Mastodon, a megafauna mammal of Minnesota. Wikimedia Commons It was only toward the very end of the Cenozoic Era--during the Pleistocene epoch, starting about two million years ago--that Minnesota truly hosted an abundance of fossil life. All sorts of megafauna mammals have been discovered in this state, including giant-sized beavers, badgers, skunk and reindeer, as well as the more familiar Woolly Mammoth and American Mastodon. All of these beasts died out by the aftermath of the last Ice Age, about 10,000 to 8,000 years ago, and may well have been encountered by early Native Americans. 04 of 04 Small Marine Organisms A bryozoan, of the type discovered in Minnesota's ancient sediments. Wikimedia Commons Minnesota has some of the oldest sediments in the United States; this state is especially rich in fossils dating from the Ordovician period, from about 500 to 450 million years ago, and it has even yielded evidence of marine life from as far back as the Precambrian period (when complex multicellular life as we know it had yet to evolve). As you may have guessed, animals back then weren't very far advanced, consisting mostly of trilobites, brachiopods, and other small, shelled marine creatures.