Hesperocyon, as the progenitor of the canid lineage, was an interesting small dog. Being only about 3 feet long and 4 pounds the "dog" was a rather small animal. It was also the only dog in the canine family with retractable claws (as far as I am aware). The body of the average Hesperocyon actually appeared much more like an extant civet than it did either a dog or a cat. The fact that it was not an arboreal living hunter make it much less like a civet or even its ancestors the Miacidae. Hesperocyon would eventually lead to a rapid radiation of canids including at least 28 members of the subfamily of Canidae, Hesperocyoninae that are most closely related to Hesperocyon. Canidae today includes a lot of species placed into two modern tribes: Canini (wolf related) and Vulpini (fox related); though this was generations away from Hesperocyon. We have seen many of those traits over this week that would continue into the descendants as well as those that would be lost, such as retractable claws.