Keen senses, large canine teeth, powerful jaws, and the ability to pursue prey at 60 km (37 miles) per hour equip the gray wolf well for a predatory way of life. A typical northern male may be about 2 meters (6.6 feet) long, including the bushy half-meter-long tail. Standing 76 cm (30 inches) tall at the shoulder, it weighs about 45 kg (100 pounds), but weight ranges from 14 to 65 kg (31 to 143 pounds), depending on the geographic area. Females average about 20 percent smaller than males. The largest wolves are found in west-central Canada, Alaska, and across northern Asia. The smallest tend to be near the southern end of their distribution (the Middle East, Arabia, and India). Fur on the upper body, though usually gray, may be brown, reddish, black, or whitish, while the underparts and legs are usually yellow-white. Light-colored wolves are common in Arctic regions.
Gray wolves usually live in packs of up to two dozen individuals; packs numbering 6 to 10 are most common. A pack is basically a family group consisting of an adult breeding pair (the alpha male and alpha female) and their offspring of various ages. The ability of wolves to form strong social bonds with one another is what makes the wolf pack possible. A dominance hierarchy is established within the pack, which helps maintain order. The alpha male and alpha female continually assert themselves over their subordinates, and they guide the activities of the group. The female predominates in roles such as care and defense of pups, whereas the male predominates in foraging and food provisioning and in travels associated with those activities. Both sexes are very active in attacking and killing prey, but during the summer hunts are often conducted alone.