Wolf Links Natural History of the Gray Wolf
Introduction and General
Description:
The gray wolf, Canus lupus,
also know as the timber wolf or tundra wolf, is the largest wild canid in North
America and has a ten to eighteen year life span. The
coloration of the gray wolf is variable, ranging from black to white. Gray wolf
coloration depends upon age and often mimics the color of the wolf’s
surroundings.
Habitat
and Range:
The primary habitats of the gray wolf
include the open tundra and forests. Before European settlement wolves
were common throughout Minnesota and most of North America. Due to a
government mandated eradication of the gray wolf during the twentieth century,
most wolves are found in Alaska, Canada, and Minnesota. Hunting, loss of
wilderness, and settlement are causes for the decline in wolf population.
Today, the total North American population is around 60,000 individuals. A
1994 estimate says Minnesota supports approximately 2,000 individuals.
Wolves are continually expanding their range to the southwest. Despite
this trend, Minnesota wolves have threatened species status. The gray wolf
is a territorial animal. The home range is defended by all members of the
pack and usually does not overlap with the ranges of neighboring packs, unless
there is a food shortage. Territory size can range anywhere from eight square
miles for a pack with abundant prey to five thousand square miles for a pack
with little prey available.
Social
Structure:
Gray wolves function in packs of two to twelve
individuals; however the size of the pack oscillates with the number of prey
available. Many of the pack members are related. An alpha male and
female wolf govern the pack. The male and females are organized in a
hierarchy of dominance based upon their power and aggression and the
subordination by other pack members. Dominance behaviors include open
mouth and bared teeth, ears erect and pointed forward, and hair raised along the
back. There are other social ranks as well. An omega wolf is seen as
the lowest wolf, and is often tormented by other pack members. Alpha
wolves are the only wolves in the pack to breed and they mate for life. An
average of seven pups are born in each litter. Other pack members often
care for the pups while the alpha females hunts. Pups eat meat regurgitated by
other pack members, including the alpha female, until they are old enough to
hunt their own meat.
Hunting
and Food:
Wolves hunt together in packs and their
strategy is simply to outrun their prey and take it down as a group. Prey
is located by following a fresh scent trail on the ground or in the air, or
simply by a chance encounter. Wolves usually hunt prey larger than itself,
such as, deer, elk, moose, caribou, bison and mountain sheep. But, they
will also catch smaller prey including rabbits, beavers, fish, and smaller
rodents. Although wolves can run approximately 30 miles per hour,
biologists estimate that less than ten percent of wolf attacks on large animals
are successful. Ideally, the wolf needs nearly two pounds of food per day
to survive, however, during times of food scarcity, wolves have been found to go
for more than two weeks without food. Minnesota's wolf population is
highly dependent upon deer. It takes about twenty deer per year to keep an
individual wolf healthy.
Communication:
The gray wolf has a variety of methods to
communicate their thoughts and emotions with members of their pack. Wolves
use yelps, whines, growls, snarls and howling to communicate. It is a
common misconception that wolves howl at the moon. Howling is an effective
method for locating pack members and displaying excitement. However,
wolves also extensively use facial expressions, body language, and tail position
to communicate.
Howling
serves to bring packs together and signal the start of a hunt, or it may be part
of waking up in the morning. Scent markings are olfactory messages that demark
a packs territory as well as breeding condition.
Breeding:
Gray wolves mate between January (low
altitudes) and April (high altitudes) and following a gestation period of
approximately 62 days, a litter of 2-11 pups are born. The pups are born in an
underground den or a small cave and are completely dependent upon their mother
for the first two months of life. Within six to eight weeks the pups are weaned
from their mother. Young gray wolves reach sexual maturity by age one and often
leave the pack by age two. They may live alone until they pair up and establish
their own territory. The life expectancy of an average gray wolf is six to
eight years, although some have been documented as living up to thirteen years
in the wild and sixteen years in captivity.
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