Daily Dose of Prehistory: Back from Extinction 67

Repenomamus giganticus, meaning "Giant Reptile Mammal", was a species of badger-sized gobiconodontid mammal that lived in what is now China during the Early Cretaceous, around 125 to 123.2 million years ago. It was among the largest Cretaceous mammals, being around 3 feet 3 inches long and weighing up to 31 pounds. Like echidnas and platypuses, Repenomamus had an epipubic bone, meaning that it laid eggs. It's one of a small number of mammals known to have preyed on small dinosaurs. In fact, the skeleton of a young Psittacosaurus, a small bipedal relative of Triceratops, were discovered in the stomach of one specimen of Repenomamus. Given its size, it likely could've taken down adult Psittacosaurus as well.