The wolf has been associated with Northern Hemisphere
people for centuries, and remains, even today, a creature of folklore
and superstition. The coloration of wolves varies greatly
from snow white to coal black and all the intermediate degrees
of cream, grey, and brown.
A large male wolf may measure over 2 m in total length
and stand almost 1 m high at the shoulders. Their weight can vary
from 26 to 80 kg. The largest wolves are found in northwestern
These animals have a well-developed social hierarchy. The
pack leader is usually the largest and strongest dog and is
followed in rank by younger or senile males, then the leader’s
mate, the other females, and finally the pups in order of
strength. All members of the pack accept responsibility for
the young, and care for other adults’ pups, if both
parents are hunting. There have been very few cases of authenticated
wolf attacks on humans in North America.
The original range of Canis lupus consisted of the majority
of the Northern hemisphere -- from the Arctic continuing
south to a latitude of 20° S, which runs through
southern Central Mexico, northern Africa, and southern
Asia. However, due to habitat destruction, environmental
change, persecution by humans, and other barriers
to population growth, gray wolf populations are
now found only in a few areas of the contiguous
United States, Alaska, Canada, Mexico (a small population),
Biogeographic Regions: nearctic (native ); palearctic
Gray wolves are one of the most wide ranging land animals.
They occupy a wide variety of habitats, from arctic tundra
to forest, prairie, and arid landscapes.
These animals are found in the following types of habitat:
temperate ; terrestrial .
Terrestrial Biomes: tundra ; taiga ; chaparral ; forest
; scrub forest ; mountains .Physical Description
20 to 75 kg
(44 to 165 lbs)
150 to 200 cm
(59.06 to 78.74 in)The largest of approximately 41 wild
species of canids. Gray wolves vary in size based primarily
on geographic locality, with southern populations generally
smaller than northern populations. Total body length,
from tip of the nose to tip of the tail, is from 1000
to 1300 mm in males, and 870 to 1170 mm in females. Tail
length ranges between 350 to 520 mm. Males can weigh
from 30 to 80 kg, with an average of 55 kg, females can
weigh from 23 to 55 kg, with an average of 45 kg. Height
(measured from base of paws to shoulder) generally ranges
from 60 to 90 cm.
Fur color of gray wolves also varies geographically,
ranging from pure white in Arctic populations, to mixtures
of white with gray, brown, cinammon, and black to nearly
uniform black in some color phases.
North American populations have three distinct color
phases. The normal phase is characterized by varying
mixtures of white with shades of black, gray, cinnamon,
and brown on the upper parts of the animal. The back
is usually more profoundly black, and the muzzle, ears,
and limbs have cinammon coloration as well. Under parts
are whitish and the tail is conspicuously black over
the tail gland, and paler below to the tip, which is
nearly pure black. The black phase of North American
populations is characterized by the upper parts varying
from brown to black, with specks of white; the underparts
are paler in tone, and there is often a pure white medial
pectoral spot. The third color phase occurs during the
first pelage of young wolves. The upper parts are drab-gray,
overlaid with brownish-black. The underparts are paler
as well, and the ears vary from black to buffy, depending
on the subspecies (Young 1944).
Gray wolves have a dense underfur layer, providing them
with excellent insulation against cold conditions.
Gray wolves can be distinguished from red wolves (Canis
rufus) by their larger size, broader snout, and shorter
ears. They are distinguished from coyotes (Canis latrans)
by being 50 to 100% larger and having a broader snout
and larger feet.Some key physical features: endothermic
; bilateral symmetry .
Sexual dimorphism: male larger.Reproduction
Gray wolves breed once each year.
Gray wolves breed between January and March, depending
on where they are living.
Number of offspring
5 to 14; avg. 7
63 days (high)
Time to weaning
45 days (average)
Age at sexual or reproductive maturity (female)
2 to 3 years
Age at sexual or reproductive maturity (male)
2 to 3 yearsThe dominant pair in a grey wolf pack are
the only members that breed. This pair is monogamous
although, with the death of an alpha individual, a new
alpha male or female will emerge and take over as the
Mating systems: monogamous ; cooperative breeder .
Breeding occurs between the months of January and April,
with northern populations breeding later in the season
than southern populations. Female gray wolves choose
their mates and often form a life-long pair bond. Gray
wolf pairs spend a great deal of time together. Female
gray wolves come into estrus once each year and lasts
5 to 14 days, mating occurs during this time. After mating
occurs, the female digs a den in which to raise her young.
The den is often dug with an entrance that slopes down
and then up again to a higher area to avoid flooding.
Pups are born in the den and will remain there for several
weeks after birth. Other dens are under cliffs, under
fallen trees, and in caves.
The gestation period lasts between 60 and 63 days, litter
size ranges from one to fourteen, with the average size
being six or seven pups. Pups remain in the den until
they are 8 to 10 weeks old. Females stay with their pups
almost exclusively for the first 3 weeks. Pups are cared
for by all members of the pack. Until they are 45 days
old the pups are fed regurgitated food by all pack members.
They are fed meat provided by pack members after that
Female pups reach maturity at two years of age, while
males will not reach full maturity until three years
of age. Most young gray wolves disperse from their natal
pack when they are between 1 and 3 years old.Key reproductive
features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious
(sexes separate); sexual ; fertilization ; viviparous
Gray wolf pups are born blind and deaf. They weigh approximately
0.5 kg and depend on the mother for warmth. At ten to
fifteen days of age, the pups' blue eyes open, but they
only have control over their front legs, thus crawling
is their only mode of mobility. Five to ten days later,
the young are able to stand, walk, and vocalize. Pups
are cared for by all members of the pack. Until they
are 45 days old the pups are fed regurgitated food by
all pack members. They are fed meat provided by pack
members after that age. During the 20th to 77th day,
the pups leave the den for the first time and learn to
play fight. Interactions at this time, as well as the
dominance status of the mother, ultimately determines
their position in the pack hierarchy. Wolf pups develop
rapidly, they must be large and accomplished enough to
hunt with the pack with the onset of winter. At approximately
ten months old, the young begin to hunt with the pack.
Parental investment: no parental involvement; altricial
; pre-fertilization (protecting: female); pre-hatching/birth
(provisioning: female, protecting: female); pre-weaning/fledging
(provisioning: male, female, protecting: male, female);
pre-independence (provisioning: male, female, protecting:
male, female); post-independence association with parents;
extended period of juvenile learning; maternal position
in the dominance hierarchy affects status of young.
Longest known lifespan in wild
13 years (high); avg. 5 years
Longest known lifespan in captivity
15 years (high)Gray wolves may live thirteen years in
the wild, though average lifespan is 5 to 6 years. As
adults they usually die from old age or from injuries
received while hunting or fighting with other wolves.
In captivity they may live to be fifteen years of age.Behavior
Gray wolves are highly social, pack-living animals. Each
pack comprises two to thirty-six individuals, depending
upon habitat and abundance of prey. Most packs are made
up of 5 to 9 individuals. Packs are typically composed
of an alpha pair and their offspring, including young
of previous years. Unrelated immigrants may also become
members of packs.
There is a strong dominance hierarchy within each pack.
The pack leader, usually the alpha male, is dominant
over all other individuals. The next dominant individual
is the alpha female, who is subordinate only to the alpha
male. In the event that the alpha male becomes injured
or is otherwise unable to maintain his dominance, the
beta male will take his place in the hierarchy. Alpha
males typically leave the pack if this occurs, but this
is not always the case. Rank within the pack hierarchy
determines which animals mate and which eat first. Rank
is demonstrated by postural cues and facial expressions,
such as crouching, chin touching, and rolling over to
show the stomach.
Each year, gray wolf packs have a stationary and nomadic
phase. Stationary phases occur during the spring and
summer, while pups are being reared. Nomadic phases occur
during the fall and winter. Wolf movements are usually
at night and cover long distances. Daily distance traveled
can be up to 200 km, the usual pace is 8 km/hr. Wolves
can run at speeds up to 55 to 70 km/hr.Home Range
The territory of a pack ranges from 130 to 13,000 square
kilometers, and is defended against intruders.Key behaviors:
cursorial; terricolous; diurnal ; nocturnal ; motile
; nomadic ; territorial ; social ; dominance hierarchies
.Communication and Perception
Rank is communicated among wolves by body language and
facial expressions, such as crouching, chin touching,
and rolling over to show their stomach.
Vocalizations, such as howling allows pack members to
communicate with each other about where they are, when
they should assemble for group hunts, and to communicate
with other packs about where the boundaries of their
territories are. Scent marking is ordinarily only done
by the alpha male, and is used for communication with
other packs.Perception channels: tactile ; chemical .Food
Gray wolves are carnivores. They hunt prey on their own,
in packs, steal the prey of other predators, or scavenge
carrion. Prey is located by chance or scent. Animals
included in the diet of gray wolves varies geographically
and depends on prey availability. Wolves primarily hunt
in packs for large prey such as moose, elk, bison, musk
oxen, and reindeer. Once these large ungulates are taken
down, the wolves attack their rump, flank, and shoulder
areas. Wolves control prey populations by hunting the
weak, old, and immature. A wolf can consume up to 9 kg
of meat at one meal. Wolves usually utilize the entire
carcass, including some hair and bones. Smaller prey
such as beavers, rabbits, and other small mammals are
usually hunted by lone wolves, and they are a substantial
part of their diet. Wolves may also eat livestock and
garbage when it is available.
Primary Diet: carnivore (eats terrestrial vertebrates).Predation
* gray wolves from other packsFew animals prey on gray
wolves. Wolves and coyotes are highly territorial animals
so wolves from other packs and coyotes will attack wolves
that are alone or young. They will kill pups if they
find them.Ecosystem Roles
As top predators, gray wolves are important in regulating
populations of their prey animals.Economic Importance
for Humans: Negative
Gray wolves may sometimes kill livestock. The extent
of livestock loss to wolves is often overstated, wolves
typically prefer their wild prey.Economic Importance
for Humans: Positive
Historically, the fur of grey wolves was used for warmth.
As top predators in many ecosystems, wolves are important
in controlling populations of their prey.
Wolves are important in our culture, many people believe
they symbolize the spirit of wilderness. Wolf products,
including posters, books, and t-shirts are very popular.
Wolf ecotourism is a major source of revenue for parks
and reserves.Ways that people benefit from these animals:
body parts are source of valuable material; ecotourism
Few animals have ever haunted our dreams or fired our
imaginations more than the wolf. Unfortunately, by the
early part of this century, man had almost exterminated
the wolf from the lower 48 states. The recovery of the
wolf is becoming an impressive conservation success story
and a gift to future generations" (Bruce Babbitt,
Secretary of the Interior).
Wolves play an important role in the ecosystem by controlling
natural prey populations and removing weak individuals.
As settlement increased, the belief that livestock was
endangered by wolf populations also increased. As such,
the frequency of hunting the gray wolf exploded. The
populations were nearly eradicated.
Currently in the lower 48 United States, about 2,600
gray wolves exist, with nearly 2,000 in Minnesota (compared
to the few hundred living there in the mid-20th century).
Successful recovery plans have been developed throughout
the country. These plans evaluate the populations to
determine distribution, abundance, and status.
The main cause of population declines has been habitat
destruction and persecution by humans. But the reintroduction
of gray wolves into protected lands has greatly increased
the likelihood of their survival in North America.
Populations in Alaska and Canada have remained steady
and are fairly numerous. Currently the State of Alaska
manages 6,000 to 8,000 gray wolves and Canada's populations
are estimated at about 50,000. The wolves in Canada are
managed by provincial governments and are not currently
In western Eurasia gray wolf populations have been reduced
to isolated remnants in Poland, Scandinavia, Russia,
Portugal, Spain, and Italy. Wolves were exterminated
from the British Isles in the 1700's and nearly disappeared
from Japan and Greenland in the 20th century. Greenland's
wolf populations seem to have made a full recovery. The
status of wolf populations throughout much of eastern
Eurasia is poorly known, but in many areas populations
are probably stable.
Except for red wolves (Canis rufus), all living North
American wolves are considered to be Canis lupus
-- a total (as of 1997) of 32 recognized subspecies.
Gray wolves are widely recognized to be the ancestor
of all domestic dog breeds (Canis lupus familiaris),
including feral forms such as dingos (Canis lupus dingo)
and New Guinea singing dogs (Canis lupus halstromi).
Genetic evidence suggests that gray wolves were domesticated
at least twice, and perhaps as many as 5 times, by humans.
Artificial selection by humans for particular traits,
including size, appearance, aggressiveness, loyalty,
and many desirable, specialized skills, has resulted
in an astonishing array of domestic dog morphologies.
Domestic dogs vary in size from diminutive, 1.5 kg chihuahuas
to 90 kg giant mastiffs.