Gray Wolf

Gray Wolf, USFWS Photo

(Canis lupus)

Physical Characteristics: 4 ½ -6 ½ feet long, 26-38 inches tall, 57-170 pounds. While a grizzled gray coat is most commonly associated with this wild dog, a wolf’s coat can range from coal black (most common in dense forests) to creamy white (characteristic of the high Arctic). Ears are short and bit more rounded than a coyote; the muzzle is short, wide, and blocky. The wolf runs with its bushy tail straight out. In social situations, the level of the tail generally relates to the social status of that individual.

Diet: Large mammals comprise 80% of this canine’s diet, mostly cervids (deer, elk, moose, caribou) and Bighorn Sheep that are hunted in family groups or “packs” of as many as 15 individuals. Wolves also devour rabbits, mice, nesting birds, and carrion when it is available.Wolves also enjoy sweet grasses, berries and nuts. Where humans leave stock unguarded, wolves may take cattle, sheep, goats, horses, dogs, cats, and pigs. Adults can eat 20 pounds of meat in a single meal. Contrary to popular belief, wolves do not take down big mammals like buffalo, moose or musk oxen for every meal. Many days, wolves go without a big feast. Hunting has dangers for the wolf, too. A kick to the head or a gore from a horn can kill or cripple a wolf.

Habitat: Although wolves formerly occupied grasslands, forest, deserts, and tundra, they are now mostly restricted to forests, streamside woodlands, and arctic tundra. Wolf dens are usually located on a rise of land near water. Most dens are bank burrows, often made by enlarging the den of a fox or burrowing mammal. Sometimes a rockslide, hollow log, or natural cave is used. Sand or soil scratched out of the entrance by the female is usually evident as a large mound. The beds from which adults can keep watch are generally found above the entrance.

Range: The historic range of gray wolves covered two-thirds of the United States. Today, grey wolves have populations in Alaska, northern Michigan, northern Wisconsin, western Montana, northern Idaho, northeast Oregon, and the Yellowstone area of Wyoming. Wolf pack territories can range from 50 to over 1,000 square miles. Conservation programs focusing intensely on grey wolves have produced reliable population data: as of 2011 the number of individuals in the contiguous US and Alaska was 17,310. Wolves were reintroduced into Idaho and Yellowstone NP in the 1990s, although they were present in low numbers in the Clearwater region at that time. Wolves remain a globally endangered species.

Reproduction: Wolves typically mate for life. In the northern United States they breed from late January through March, are pregnant for about 63 days, and usually birth four to six pups. Pups are weaned at about six weeks and are then fed regurgitated food brought in by adults until old enough to follow in the hunt. The mother moves her den every couple of months until the fall when the pack stops living at den sites. Packs usually range from four to nine members, occasionally growing up to thirty members until some individuals break off to find their own territory and form their own pack. A social hierarchy is strictly followed in the pack; often, only the top animals (the “alpha” male and female) will reproduce, but other pack members help with bringing food to the pups and defending the group’s territory against intrusions of other wolves. In the wild, lifespan averages 8 years.

Threats: Habitat destruction and fragmentation due to human development comprises only part of the threat to wolves. The canine has been officially delisted from the Endangered Species Act, and legislation allowing trapping, aerial gunning, and general hunting of wolves remains a fiercely contested debate. In the North American imagination, the Grey Wolf often either symbolizes the pinnacle of all that is wilderness, or is the hated menace to domestic animals, ranchers, and the “conquest and civilizing” of the West.

Miscellaneous: Wolves are capable of many facial expressions such as pursed lips, smile-like submissive grins, upturned muzzles, wrinkled foreheads, and angry squinting eyes. Wolves even stick their tongues out at each other as a gesture of appeasement or submission. Wolves bark as a warning; a playful wolf dances and bows; howling is a way to communicate over long distances in order to pull a pack back together and to keep strangers away. Body language, scent marking, and growling are other modes of sophisticated communication that generally serve to reinforce the social hierarchy of the pack.

Learn about our collective efforts to keep US Fish & Wildlife Service involved with monitoring gray wolves.


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