2.7" Fossil Oreodont (Leptauchenia) Partial Mandible - South Dakota

Because the eyes and nostrils were placed high on the head, it was long assumed that Leptauchenia was an aquatic or semi-aquatic animal. However, because their fossils have never been found in floodplain deposits or river channels but are found abundantly abundance in fossil sand dunes, paleontologist Donald Prothero suggests that they were desert-dwelling animals. According to Prothero's interpretation, the high-placed eyes and nostrils served to filter out sand while burrowing, or while digging themselves free of sand dunes.