WOLF,
common name for the species of animals that, with jackals
and domestic dogs, make up the genus Canis, family
Canidae. Two species—and a varying number of subspecies—of
wolves are recognized: the gray, or timber, wolf, C. lupus, once
widely distributed in North America, Europe, and Asia; and the red
wolf, C. rufus, which now occurs only in Texas
and Louisiana. An adult timber wolf measures up to 1.6 m (6.5 ft)
in length, including the tail (which is less than half the body
length), and may weigh up to 80 kg (175 lb). The animal is red-yellow
or yellow-gray, with black patches above and white below; those
in the far north, however, may be pure white, and black or brown
timber wolves also occur. The red wolf is somewhat smaller in size
and usually darker in color, and may represent a cross with the
COYOTE. All wolves are characterized by powerful teeth, bushy tails,
and round pupils, and they are distinguished from domestic dogs
(some breeds of which they otherwise resemble) by certain characteristics
of the skull.
Wolves are equally at home on prairies, in forestlands, and
on all but the highest mountains, but they are not found on desert
lands. In the winter they travel in packs in search of food. Small
animals and birds are the common prey of wolves, which also eat
berries, but a pack may sometimes attack reindeer, sheep, and other large
mammals, usually selecting weak, old, or very young animals for
easier capture. When no live prey can be found, wolves feed on carrion.
The den, or lair, of the wolf may be a cave, a hollow tree
trunk, a thicket, or a hole in the ground dug by the wolf. The breeding
season is in the spring, and the female has a litter of three to
nine cubs. The cubs normally stay with the parents until the following
winter but may remain much longer. Parents and young constitute
a basic pack, which establishes and defends a territory marked by
urine and feces. Larger packs may also assemble, particularly in
the winter; the pack leader is called the alpha male, and its mate
is the alpha female. As social animals, wolves exhibit behavioral
patterns that clearly communicate dominance over or submission to
one another; the communal howling of a pack may serve to assemble
its members, communicate with other packs, advertise its territorial
claims, or simply be a source of pleasure.
Although wolves are still abundant in eastern Europe and in
Asia, only remnant populations now exist in western Europe, and
their numbers in the New World also have been greatly diminished.
They are fairly abundant in Alaska and Canada, but remnant populations
of timber wolves south of Canada occur only in Minnesota and Mexico.
The decreasing numbers of wolves are the result of encroachments
on their territory by humans, who have long regarded wolves as competitors
for prey and as dangerous animals in themselves. The fact is that
few, if any, healthy wolves have attacked humans, whom they instead
try to avoid, and wolves are valuable predators in the FOOD WEB.
Their decimation has led to the overpopulation of a number of other
animal species in various areas. Humans have also used wolves, in
that sledge dogs are often crossbred with wolves to improve the
vigor of the stock.
Natural recolonization of wolves began in the late 1970s in
and around Glacier National Park in northwestern Montana. In January
1995 the U.S. government began a controversial program, supervised
by the Fish and Wildlife Service, of reintroducing the endangered
North American gray wolf to Yellowstone National Park in Wyoming
and to a wilderness area in central Idaho.