Very few people get excited about spotting an opossum in the wild. In fact, opossums would likely scare any person who spotted one, especially young children. This is because opossums are strange and very different looking mammals. Not many mammals in the wild are sporting frightening fangs, and a menacing sneer, which seems to be the expression that an opossum's natural resting face shows. It would not surprise you to hear that opossums deserve more respect, but not many mammals alive today can claim to have been around when the dinosaurs commonly roamed the planet. According to recently uncovered evidence, opossums have inhabited this planet since the Upper Cretaceous Period, and this was a time when dinosaurs were still alive and well on this planet. Not only that, but opossums, which are the only marsupials known to dwell in America, all originated on the North American continent. Several years ago, a fossilized skull was found in the bighorn basin located on Wyoming. The skull was found to be fifty five million years old. A high resolution CT scan was used to date the fossil. To be clear, the fossilized skull was not identical to the shape and form of modern marsupial skulls. Rather, the fossil that was discovered in Wyoming contained the skull of a particular family of marsupials known as peradectids. The peradectids are now extinct, but they are closely related to modern marsupials. These peradectids first appeared on North American soil around sixty five million years ago, which was around the same time that dinosaurs began going extinct. As the dinosaurs died out, mammals flourished. Based on fossil evidence, researchers seem nearly certain that the evolutionary split between the ancient opossums and all other living marsupials occurred at least sixty five million years ago. If you were not aware that opossums were as old as they are, then which mammal did you believe was the oldest?