The average healthy wolf pack contains 7-9 wolves weighing 70-130 pounds. Sometimes they can weigh as much as 180 pounds. The pack is very well organized and strictly well organized the the alpha male and female. These two wolves mate for life and are the only ones able to mate and reproduce. Moose is a main meal for wolves. If their is a sick or injured animal they will single it out. 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.