Wolf packs are led by an alpha male and his mate, and they fight other wolves to win their leaders-of-the-pack positions. When wolves raise their tail that means I am the leader of the pack. Leaders of most wild packs are simply parents. The size of a wolf depends on where it lives. In the northern part of their geographical range, wolves tend to grow larger and have thicker fur and bigger feet. Northern wolves can weigh up to 130 pounds(59kg), while southern wolves are much smaller, weighing in at about 50 pounds(23kg). Some wolves in the Middle East may weigh as little as 30 pounds(14kg).