The genus Canis includes wolves, coyotes, jackals, and the domestic dogs. In the midwestern U.S. at least three members of the genus are found in sites that date from the last Ice Age. These three members are the dire wolf (Canis dirus), the gray wolf (Canis lupus) and the coyote (Canis latrans). One additional species, the domestic dog (Canis familiaris), was almost certainly also present at the very end of the Pleistocene (after about 12,000 years ago).
The gray wolves and coyotes of the last Ice Age were probably very similar in look and behavior to their modern relatives. The dire wolf was not quite like any animal surviving today. It was similar in overall size and mass to a large modern gray wolf. This means 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 were much larger and more massive than those of the gray wolf. They may have been used to crush bones.
The braincase of the dire wolf was also smaller than that of a similarly-sized gray wolf. The jaws of the dire wolf and grey wolf also show the larger size of the dire wolf’s teeth.
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 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, California. The coyote, gray wolf, and dire wolf have all been found in paleontological sites in the midwestern U.S.
The fact that the lower parts of the legs of the dire wolf are proportionally shorter than those of the gray wolf indicates that the dire wolf was probably not as good a runner as the gray wolf.
The genus Canis underwent a mixed fate at the end of the Pleistocene. The gray wolf and coyote survived the extinction that occurred approximately 11,500 years ago. The dire wolf, however, was one of the animals that did not survive. Perhaps the dire wolf depended on scavanging 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 11,500 years ago.