© 2004 Robert F. Walters

This mammal is called Didelphodon. Didelphodon was a carnivore and an extinct relative of modern marsupials. Reaching the size range of the modern Virginia opossum, Didelphodon is much larger than many other tiny mammals that co-existed with dinosaurs such as the new oviraptorosaur, Triceratops and Tyrannosaurus rex at the end of the Cretaceous in North America. Its very robust cheek teeth (called premolars) and strong jaw were useful for either crushing the bones of small vertebrate animals or for eating hard food items such as shelled invertebrates.

It has been speculated that Didelphodon had a preference for aquatic habitats because the wear pattern on its teeth is very similar to that of the modern sea otter, and because its skeleton shows some features that may be adaptations for aquatic living. Its fossils are mostly known from river deposits.