Paul Simmerly, age 10, of Huntsville. Ala., for his question:
From what animal did the dog descend?
We know Bowser as the faithful friend of the human family. But his recent ancestors were wolf-like animals of the wild. His family tree, however, goes much farther back to animals that resemble the dog only slightly. We would not recognize these ancestors of our faithful Bowser.
Scientists have tried to trace back the family tree of the dog with the help of fossils long buried in the ground. Many of these old dog bones have been found and assembled to give an idea of what their owners were like. But experts are not sure that all of these somewhat dog like animals of the past actually were ancestors of our dogs. There is a vast assortment of dogs large and small in the modern dog clan. There also seems to have been a vast assortment of very different animals in the family tree of the dog world.
The earliest known dog ancestor could have been an animal that roamed our land some million years ago. Scientists have assembled his fossilized bones and named him Miacis. He was a small and slender fellow with a pointed nose and short legs, catty claws and a very long tail. He shared his world with herds of sheep sized horses and humpless camels no bigger than deer. The little meat eater may have spent most of his time hunting for food among the treetops.
Some five million years later, the world was inhabited by two animals that may or may not belong in the dog family tree. One was a heavy, big headed bear type dog. He was the size of a coyote, and experts have named him Daphaenus. Through the ages, the children of Daphaenus grew bigger and bulkier, and some 10 million years ago they emerged as the ancestors of the bear clan. Bears and dogs are closely related, and in the dim past they may have shared a common ancestor.
The other dog type animal of 35 million years ago was Cynodictis. He was smaller and slimmer than the bear dog, and like ancient Miacis he had a pointed nose, short legs, a long tail and cat type claws. We are fairly sure that Cynodictis was an ancestor of modern dogdom. One of his descendants gave rise to the hunting dogs of Africa and India. Another has been named Tomarctus. He lived some 25 million years ago, and his children include the wolves and wild dogs of the modern world, the clever foxes and coyotes and all the faithful dogs that share our lives.
The dog family has been developing for at least 40 million years, and during this long time the offspring have taken many different forms. One member of the family gave rise to the bears and other types died out. The experts have been unable to trace back the dog ancestors in a single direct line to the very beginning of their history.