Canis lupus 
     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 Canada. 
     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. 

Geographic Range
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), and Eurasia.
Biogeographic Regions: nearctic (native ); palearctic (native ).Habitat
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
Mass
20 to 75 kg
(44 to 165 lbs)
Length
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
Breeding interval
Gray wolves breed once each year.
Breeding season
Gray wolves breed between January and March, depending on where they are living.
Number of offspring
5 to 14; avg. 7
Gestation period
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 mate.
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 age.
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.
Lifespan/Longevity
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 Habits
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
Known predators
* coyotes
* 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 .Conservation Status
Conservation status
Endangered
" 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 threatened.
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.

Other Comments
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.