The previous few weeks of September I devoted to a request kindly worded, but this final week of September I have made my own pick for our discussions. Given that the Miacidae were a very cat and/or dog like group of organisms, I have decided on an early canid mammal. The mammal for this week is Hesperocyon Scott 1890. Hesperocyon includes two species; H. coloradensis and H. gregarius (type). The first of the dog related groups (Hesperocyoninae, Borophaginae, Caninae) to evolve that includes extant canids, Hesperocyon still possessed many feline traits found in the Miacidae prior to the branching of the two groups. The oldest fossils were dated at 42 mya (from Saskatchewan) and the youngest at 31 mya (from Wyoming). These were small canids, only reaching about 4 lbs (1.8 kg) and 2.8 feet (80 cm).