Since Amphicyonids resemble both Bears and Dogs, They became known as “Bear-dogs”. These Carnivores had skulls similar to Dogs but feet and claws similar to Bears. In addition, various Members of the Bear-dog Family had bodies that ranged from being Dog-like to Bear-like. In fact, scientists once thought that Amphicyonids were “true dogs”, but now regard Them to be closer kin to Bears.
From the Eocene to the Pleistocene epoch (about forty-six million years ago to two million years ago), Members of the Bear-dog Family lived in Africa, Eurasia, and North America. Bear-dogs ranged from fast-moving meat eaters who looked like Dogs to Panda-like scavengers. Possessing sharp claws, many of the Bear-dogs were active diggers who dug out Rodents out of their burrows for food. Denning in steep river banks, Bear-dogs would line their homes with fur and soft leaves. Meanwhile, other Bear-dogs scavenged by driving other Animals away from their kills. However these versatile Carnivores became extinct when They were unable to compete with “true Bears”, who emerged during the Pleistocene epoch.
Bear-dogs point to the hazards of using our time to measure and analyze deep time. For example, a close relative of Amphicyonids was Cynodictis, who was once thought to be the first “true dog” (which turned out to be false). Although Bear-dogs are now traditionally regarded as relatives of Bears, that also is in doubt. Upon further study, Bear-dogs may be placed in their own grouping of Carnivores.
The evolution of Dog is more complex than first realized. The first Dogs were Hesperocyons, who emerged in North America. Later Bears split off from the Doglike branch of Carnivores. Meanwhile, Bear-dogs existed before and alongside various Members of the Dog Family.
Bear-dogs, by virtue of their fluidity, challenge us to establish new ways of seeing deep time. Since our time is unlike deep time, we have little to compare this time with. Therefore when we go into deep time, we must leave our preconceived notions behind. However, we should not leave our sensible judgment behind. By being sensible but not static, we can be more accurate in our judgments. Bear-dogs will not allow us to stagnate in deep time, but will keep us as fluid as They are.