The Evolutionary history of the wolf is not totaly clear, but many biologists believe that the wolf developed from primitive carnivores known as miacids. Miacids ranged from gopher-sized to dog-sized animals, and appeared in the Lower Tertiary about fifty two million years ago. Miacids in turn had evolved from Cretaceous insectivores. The direct descendants of miacids today are animals called viverrids, which include the genet of Africa.
Relatively late in the evolutionary history of miacids came the appearance of the first canid (Cynodictis), one of these was called the dawn-wolf, this creature had a long body and looked like a enlongated fox, it could live and climb in trees, it was also thought to possibly related to feline species. Some authorities believe that canids originated in North America and then spread to Asia and South America, while others ascribe that a small type of wolf crossed into siberia from alaska, where it eventually developed into the larger, present-day grey wolf. The grey wolf then migrated to North America, where it populated what is now Canada and the United States, except for the southeastern section of the latter country. that area was populated by the smaller red wolf(C. rufus). Still Others believe that the dog family originated in North America, migrated to Asia, and then returned
Wolf ancestors began to develop in the Paleocene, about sixty million years ago. By the Miocene, about twenty million years ago, canines and felines had branched into two separate families. In one ancestor of the wolf,Tomarctus, the fifth toe on the hind leg became vestigal and is evidenced today by the dew claw on both wolves and dogs.
Research of wolf history by Robert Wayne at the University of California suggests that a number of wolflike canids diverged from a common ancestor about two to three million years ago. The first gray wolf,(Canis Lupis), probably appeared in Eurasia sometime in the early Pleistocene period about a million years ago. Around 750,000 years ago, it is though to have migrated to North America.
The Dire Wolf,(Canis Dirus), larger and heavier than the gray wolf, evolved earlier and the two co existed in North America for about 400,000 years. As prey became extinct around 16,000 years ago due to climatic change, the dire wolf gradually became extinct itself. Around 7,000 years ago the gray wolf became the prime canine predator in North America
The Dire Wolf
The dire wolf was a large canine that exhibited hyena like characteristics. Like thehyena, the dire wolf hunted and scavenged for food. Researchers suspect that dire wolves, due to their scavenging nature, scattered the bones of animals they killed or that were killed by other prey.
The dire wolf was not quite like any animal we have today. It was similar in overall size and mass to a large modern gray wolf.
(A popular misconception is that dire wolf dwarfed the modern day grey wolf)
It was about 1.5 meters (5 feet) long and weighed about 50 kilograms (110 pounds) on average. The dire wolf looked fairly similar to the modern gray wolf; however, there were several important differences. The dire wolf had a larger, broader head and shorter, more sturdy legs than its modern relative. The teeth of dire wolf much larger and more massive than those of the gray wolf. The braincase of the dire wolf is also smaller than that of a similarly-sized gray wolf. The fact that the lower part of the legs of the dire wolf are proportionally shorter than those of the gray wolf, indicates that the dire wolf was probably not a good a runner as the gray wolf.
Many paleontologists think that the dire wolf may have used its relatively large, massive teeth to crush bone. This idea is supported by the fact that dire wolf teeth frequently have large amounts of wear on their crowns. Several people have suggested that dire wolves may have made their living in similar ways to the modern hyenas. Wolves and coyotes are relatively common large carnivores found in Ice Age sites. In fact, several thousand dire wolves have been found in the asphalt pits at Rancho La Brea in Los Angeles, CA. The coyote, gray wolf, and dire wolf have all been found in paleontological sites in the midwestern U.S.
The first specimen of a dire wolf was found at near Evansville, Indiana. Clark Kimberling of the University of Evansville has traced the very interesting history of this specimen.
The Evolution of the Genus Canis
The genus Canis underwent a mixed fate at the end of the Pleistocene. The gray wolf and coyote survived the extinction thatoccurred approximately 10,000 years ago. The dire wolf, however, was one of the animals that did not survive. Perhaps the dire wolf depended on scavenging the remains of the large herbivores of the last Ice Age. The extinction of these herbivores may have then led to the extinction of the dire wolf. Scientists do not know if this is the case; however, they continue to search for the reason that many kinds of mammals went extinct about 10,000 years ago.
The evolution of these three species of canids is very interesting. Paleontologists think that, although all three of the species were found in the same area at the same time, each comes from a different evolutionary lineage within the genus Canis. That is, none of these three species is the direct ancestor of either of the other two species.
The grey wolf was well was established in North America by the time the first Native American and Inuit Peoples came across the Beringia, about eighteen thousand years ago.
The Evolution of the domestic dog is still a matter of much debate. Some Believe that the dog is descended from the wolf, while others think they are evolved separately from a common ancestor. Recently the American Society of Mammologist recommended that the domestic dog be reclassified as a new subspecies of wolf, Canis lupus familiaris. There is some genetic evidence that the dog is descendent from the wolf and that the domestication of the dog took place several times over the course of history.