Hesperocyon, or the humble origins of the dog family
The dog family, the Canidae, includes today such formidable predators as the wolf, the Asian dhole and the African wild dog, efficient group hunters of large prey. But over 36 million years ago, when the earliest fossil canids are recorded, dogs would make a rather modest sight. It was the late Eocene, and most mammals were creatures of moderate size -there was no single animal on land to rival the body mass of a modern elephant, for instance. North America, the continent where the dog family had its origin, was largely covered by forests, and that would be the habitat where the earliest canid would thrive.
Paleontologists know that earliest dog as Hesperocyon (meaning “Dog from the West”), and the animal was about the size of a domestic cat. Its body proportions resemble those of a genet more than those of any dog. It had short ferelimbs, long hindlimbs and a long back and tail, proportions that suggest an agile animal well able to move quicky in the forest floor, jumping and veering around obstacles and climbing when neccesary.
Unlike most modern dogs, this was no ling-distance runner, and it didn’t need to. Spending most of its time in a forested habitat it is likely that most of the resources it needed were relatively nearby.
From such humble origins the dog family evolved into an astonishign variety of shapes and sizes, but most of the more striking forms are unfortunately extinct. Even so, extant dogs are still an impressive bunch, with over 35 species ranging in size from the diminutive fennec to the impressive gray wolf. All that diversity sprang from the unprepossesing stock of Hesperocyon, a creature whose small size and adaptability gave it an almost unlimited evolutionary potential.