There are about 1500 to 1900 wolves in Minnesota, mostly in the northeast. Isolated reports of a few individuals have been made in Idaho, Washington, North Dakota, and a few other states. Currently, there is a reintroduction program in progress to reinstate wolves into the Yellowstone National Park area, where they are the only animals lacking in what will soon be a complete ecosystem. Most adult male wolves weigh between 80 to 110 pounds, with females usually weighing 10 to 20 pounds less. They usually weigh 15 to 20 pounds more in the winter than in the summer due to a heavier fur coat, among other things.
Wolves have a double layer of fur.
A wooly underfur grows very thick in the fall and winter and keeps the wolf warm, while an outer layer of guard hairs repels snow and water, and keeps the underfur dry so it can trap air as an insulator. In this way, it can easily survive temperatures will below zero. During the spring, the thick underfur sheds so the wolf can survive the heat. Wolves are social animals, living together in family groups called packs. In order to live together peacefully, they have an elaborate system of rank order.