The wolf is the largest member of the canine family. Gray wolves range in color from grizzled gray or black to all-white. As the ancestor of the domestic dog, the gray wolf resembles German shepherds or malamutes. Wolves are making a comeback in the Great Lakes, northern Rockies and Southwestern United States.
Diet
Wolves eat ungulates, or large hoofed mammals, like elk, deer, moose and caribou. Wolves are also known to eat beaver, rabbits and other small prey. Wolves are also scavengers and often eat animals that have died due to other causes like starvation and disease.
Population
There are an estimated 7,000 to 11,200 wolves in Alaska and more than 5,000 in the lower 48 states. Around the world there are an estimated 200,000 in 57 countries, compared to up to 2 million in earlier times.
Range
Wolves were once common throughout all of North America but were killed in most areas of the United States by the mid 1930s. Today their range has been reduced to Canada and the following portions of the United States: Alaska, Idaho, Michigan, Minnesota, Montana, Wisconsin and Wyoming. Mexican wolves are found in New Mexico and Arizona.
Thanks to the reintroduction of wolves in 1995, Yellowstone National Park is one of the most favored places to see and hear wolves in the native habitat.
Behavior
Wolves live, travel and hunt in packs of 4-7 animals on average. Packs include the mother and father wolves, called the alphas, their pups and several other subordinate or young animals. The alpha female and male are the pack leaders that track and hunt prey, choose den sites and establish the pack's territory. Wolves develop close relationships and strong social bonds. They often demonstrate deep affection for their family and may even sacrifice themselves to protect the family unit.
extraído de http://www.defenders.org/wildlife_and_habitat/wildlife/wolf,_gray.php
