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Gray Wolf

2007 Schools Wikipedia Selection. Related subjects: Mammals

                    iGray Wolf

                             Conservation status

   Least Concern (LC)
            Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Mammalia
   Order:   Carnivora
   Family:  Canidae
   Genus:   Canis
   Species: C. lupus

                                Binomial name

   Canis lupus
   Linnaeus, 1758

   The Gray Wolf (Canis lupus; also spelled Grey Wolf, see spelling
   differences; also known as Timber Wolf or Wolf) is a mammal in the
   order Carnivora. The Gray Wolf shares a common ancestry with the
   domestic dog (Canis lupus familiaris), as evidenced by DNA sequencing
   and genetic drift studies. Gray wolves were once abundant and
   distributed over much of North America, Eurasia, and the Middle East.
   Today, for a variety of human-related reasons including widespread
   habitat destruction and excessive hunting, wolves inhabit only a very
   limited portion of their former range.

   The Gray Wolf, being a keystone predator, is an integral component of
   the ecosystems to which it typically belongs. The wide range of
   habitats in which wolves can thrive reflects their adaptability as a
   species, and includes temperate forests, mountains, tundra, taiga, and
   grasslands. In the contiguous United States, with the exception of
   Minnesota and Wisconsin (where they have a threatened status), they are
   listed as endangered under the Endangered Species Act of 1973. They
   continue to be hunted in many areas of the world as perceived threats
   to livestock and humans, as well as for sport.

Anatomy, physiology, and reproduction

Features and adaptations

   Wolf weight and size can vary greatly worldwide, though both tend to
   increase proportionally with higher latitudes. Generally speaking,
   height varies from 0.6–0.8 meters (26–32 inches) at the shoulder, and
   weight can range anywhere from 23–59 kilograms (50–130 pounds), making
   wolves the largest among all wild canids. Although rarely encountered,
   extreme specimens reaching over 77 kg (170 lb) have been recorded in
   Alaska and Canada, and the heaviest wolf on record, which was killed in
   Alaska in 1939, weighed 80 kg (175 lb). The smallest wolves come from
   the Arabian Wolf subspecies, the females of which may weigh as little
   as 10 kg (22 lb) at maturity. Customarily, however, wolves will be of a
   more typical physical capacity, with the females in a given population
   weighing about 20% less than their male counterparts. Wolves can
   measure anywhere from 1.3–2 meters (4.5–6.5 feet) from nose to tail
   tip, with the tail itself consisting of approximately one quarter of
   overall body length.

   Wolves are built for stamina, possessing features tailored for
   long-distance travel. Narrow chests and powerful backs and legs
   contribute to the wolf's proficiency for efficient locomotion. They are
   capable of covering several miles trotting at about a 10 km/h (6 mph)
   pace, though they have been known to reach speeds approaching 65 km/h
   (40 mph) during a chase (wolves only run fast when testing potential
   prey). While sprinting thus, wolves can cover up to 5 meters (16 ft)
   per bound.
   Wolves usually have blended pelages.
   Enlarge
   Wolves usually have blended pelages.

   Wolf paws are able to traverse easily through a wide variety of
   terrains, especially snow. There is a slight webbing between each toe,
   which allows wolves to move over snow more easily than comparatively
   hampered prey. Wolves are digitigrade, so the relative largeness of
   their feet helps to better distribute their weight on snowy surfaces.
   The front paws are larger than the hind paws, and feature a fifth
   digit, a dewclaw, that is absent on hind paws. Bristled hairs and blunt
   claws enhance grip on slippery surfaces, and special blood vessels keep
   paw pads from freezing. Furthermore, scent glands located between a
   wolf's toes leave trace chemical markers behind, thereby helping the
   wolf to effectively navigate over large expanses while concurrently
   keeping others informed of its whereabouts.

   A wolf sometimes seems more massive than it actually is due to its
   bulky coat, which is made of two layers. The first layer consists of
   tough guard hairs designed to repel water and dirt. The second is a
   dense, water-resistant undercoat that insulates. Wolves have distinct
   winter and summer pelages that alternate in spring and autumn. Females
   tend to keep their winter coats further into the spring than males.

   Coloration varies greatly, and runs from gray to gray-brown, all the
   way through the canine spectrum of white, red, brown, and black. These
   colors tend to mix in many populations to form predominantly blended
   individuals, though it is certainly not uncommon for an individual or
   an entire population to be entirely one colour (usually all black or
   all white). A multicolor coat characteristically lacks any clear
   pattern other than it tends to be lighter on the animal's underside.
   Fur colour sometimes corresponds with a given wolf population's
   environment; for example, all-white wolves are much more common in
   areas with perennial snow cover. Aging wolves acquire a grayish tint in
   their coats.
   Adolescent wolf with golden-yellow eyes.
   Enlarge
   Adolescent wolf with golden-yellow eyes.

   At birth, wolf pups tend to have darker fur and blue eyes that will
   change to a yellow-gold or orange colour when the pups are 8–16 weeks
   old. Though extremely unusual, it is possible for an adult wolf to
   retain its blue-colored eyes.

   Wolves have stout, blocky muzzles that help distinguish them from
   coyotes and wolf-like dogs. Wolves also differ in certain skull
   dimensions, having a smaller orbital angle, for example, than dogs (
   >53 degrees for dogs compared to <45 degrees for wolves) while
   possessing a comparatively larger brain capacity. Larger paw size,
   yellow eyes, longer legs, and bigger teeth further distinguish adult
   wolves from other canids, particularly dogs. Also, precaudal glands at
   the base of the tail are present in wolves but not in dogs.

   Wolves and most larger dogs share identical dentition; the maxilla has
   six incisors, two canines, eight premolars, and four molars. The
   mandible has six incisors, two canines, eight premolars, and six
   molars. The fourth upper premolars and first lower molars constitute
   the carnassial teeth, which are essential tools for shearing flesh. The
   long canine teeth are also important, in that they are designed to hold
   and subdue the prey. Powered by 1500 lb/sq. inch of pressure, a wolf's
   teeth are its main weapons as well as its primary tools. Therefore, any
   injury to the jaw line or teeth could devastate an individual, dooming
   it to starvation or incompetence.

Courtship and mating

   Usually, the instinct to pass on genetic material drives young wolves
   away from their birth packs, leading them to seek out mates and
   territories of their own. Dispersals occur at all times during the
   year, typically involving wolves who reached sexual maturity during the
   previous breeding season. It takes two such dispersals from two
   different packs for the process to take place, as dispersing wolves
   from the same maternal pack tend not to mate. Once two dispersing
   wolves meet and begin traveling together, they immediately begin the
   process of seeking out territory, preferentially doing so in time for
   the next mating season. The bond that forms between such wolves often
   lasts for the shorter of the two lifetimes, with few exceptions.

   During the mating season, breeding wolves become extremely affectionate
   with one another in anticipation for the female's ovulation cycle.
   Overall, pack tension rises, as each mature wolf begins to feel the
   urge to mate. In fact, during this time, the alpha male and alpha
   female may be forced to aggressively prevent other wolves from mating
   with each other. Under normal circumstances, a pack can only support
   one litter per year, so this type of dominance behaviour is beneficial
   in the long run.

   When the alpha female goes into estrus—a phenomenon that occurs once
   per year and lasts 5–14 days,—she and her mate will spend an increased
   amount of time in seclusion. Pheromones in the female's urine and the
   swelling of her vulva let the male know when his mate is in heat. She
   will be unreceptive for the first few days of estrus, during which time
   she sheds the lining of her uterus. Once the female begins to ovulate,
   mating occurs.

   The male wolf will mount the female firmly from behind. After achieving
   coitus, the two form a copulatory tie once the male's bulbus glandis—
   an erectile tissue located near the base of the canine penis— swells
   and the female's vaginal muscles tighten. Ejaculation is induced by the
   thrusting of the male's pelvis and the undulation of the female's
   cervix. The two become physically inseparable for anywhere from 10–30
   minutes, during which period the male will ejaculate multiple times.
   After the initial ejaculation, the male may lift one of his legs over
   the female such that they are standing end-to-end; this is believed to
   be a defensive measure. The mating ordeal is repeated many times
   throughout the female's brief ovulation period, which occurs once per
   year per female, unlike female dogs, with whom estrus usually occurs
   twice per year.

Breeding and life cycle

   A wolf pup looks up to others in the pack for protection.
   Enlarge
   A wolf pup looks up to others in the pack for protection.

   Normally, only the alpha pair of the pack breeds, which is a kind of
   organization not uncommon to other pack-hunting canids including the
   Dhole and the African Hunting Dog. Mating occurs between January and
   April, happening later in the year as latitude increases. A pack
   usually produces a single litter, though sometimes multiple litters
   will be born if the alpha male mates with one or more subordinate
   females. Under normal circumstances, the alpha female will try to
   prevent this by aggressively dominating other females and physically
   separating them from the alpha male during the mating season.
   A wolf resting at the entrance to its den; also note how its coloration
   blends in with the environment.
   Enlarge
   A wolf resting at the entrance to its den; also note how its coloration
   blends in with the environment.

   The gestation period lasts 60–63 days, and at the weight of 0.5 kg (1
   lb), the pups are born blind, deaf, and completely dependent on their
   mother. There are 1–14 pups per litter, with the average litter size
   being about 4–6. Pups reside in the den, where they are born, and stay
   there until they reach about 3 weeks of age. The den is usually on high
   ground near an open water source, and has an open "room" at the end of
   an underground or hillside tunnel that can be up to a few meters long.
   During this time, the pups will become more independent, and will
   eventually begin to explore the area immediately outside the den before
   gradually roaming up to a mile away from it at around 5 weeks of age.
   They begin eating regurgitated foods after 2 weeks— by which time their
   milk teeth have emerged— and are fully weaned by 8–10 weeks. During the
   first weeks of development, the mother usually stays with her litter
   alone, but eventually most members of the pack will contribute to the
   rearing of the pups in some way.

   After 2 months, the restless pups will be moved to a rendezvous site,
   which gives them a safe place to reside while most of the adults go out
   to hunt. An adult or two will stay behind to ensure the safety of the
   pups. After a few more weeks, the pups are permitted to join the adults
   if they are able (they tag along as observers until about 8 months, by
   which time they are large enough to actively participate), and will
   receive first priority on anything killed, their low ranks
   notwithstanding. Letting the pups fight for eating privileges results
   in a secondary ranking being formed among them, and allows them to
   practice the dominance/submission rituals that will be essential to
   their future survival in pack life.
   A wolf in captivity at the Beardsley Zoo in Connecticut.
   Enlarge
   A wolf in captivity at the Beardsley Zoo in Connecticut.

   Wolves typically reach sexual maturity after 2 or 3 years, at which
   point many of them will feel compelled to leave their birth packs and
   search out mates and territories of their own. Wolves that reach
   maturity generally live 6–8 years in the wild, although in captivity
   they can live to be twice that age. High mortality rates result in a
   relatively low life expectancy for wolves on an overall basis. Pups die
   when food is scarce; they can also fall prey to other predators such as
   bears, or, less likely, coyotes, foxes, or other wolves. The most
   significant mortality factors for grown wolves are hunting and poaching
   by humans, car accidents, and wounds suffered while hunting prey.
   Wolves are susceptible to the same infections that affect domestic
   dogs, such as mange, heartworm, rabies and canine distemper, and such
   diseases can become epidemic, drastically reducing the wolf population
   in an area.

Behaviour

Body language

   This facial expression is defensive and gives warning to other wolves
   to be cautious.
   Enlarge
   This facial expression is defensive and gives warning to other wolves
   to be cautious.
   This facial expression shows fear.
   Enlarge
   This facial expression shows fear.
   This wolf's submissive posture, wagging tail and horizontal ears show a
   friendly greeting.
   Enlarge
   This wolf's submissive posture, wagging tail and horizontal ears show a
   friendly greeting.

   Wolves can visually communicate an impressive variety of expressions
   and moods that range from subtler signals, such as a slight shift in
   weight, to the more obvious ones, like rolling on the back as a sign of
   complete submission.
     * Dominance – A dominant wolf stands stiff legged and tall. The ears
       are erect and forward, and the hackles bristle slightly. Often the
       tail is held vertical and curled toward the back. This display
       shows the wolf's rank to all others in the pack. A dominant lupine
       may stare penetratingly at a submissive one, pin it to the ground,
       "ride up" on its shoulders, or even stand on its hind legs.
     * Submission (active) – In active submission, the entire body is
       lowered, and the lips and ears are drawn back. Sometimes active
       submission is accompanied by muzzle licking, or the rapid thrusting
       out of the tongue and lowering of the hindquarters. The tail is
       placed down, or halfway or fully between the legs, and the muzzle
       often points up to the more dominant animal. The back may be
       partially arched as the submissive wolf humbles itself to its
       superior; a more arched back and more tucked tail indicate a
       greater level of submission.
     * Submission (passive) – Passive submission is more intense than
       active submission. The wolf rolls on its back and exposes its
       vulnerable throat and underside. The paws are drawn into the body.
       This is often accompanied by whimpering.
     * Anger – An angry lupine's ears are erect, and its fur bristles. The
       lips may curl up or pull back, and the incisors are displayed. The
       wolf may also arch its back, lash out, or snarl.
     * Fear – A frightened wolf tries to make its body look small and
       therefore less conspicuous. The ears flatten down against the head,
       and the tail may be tucked between the legs, as with a submissive
       wolf. There may also be whimpering or barks of fear, and the wolf
       may arch its back.
     * Defensive – A defensive wolf flattens its ears against its head.
     * Aggression – An aggressive wolf snarls and its fur bristles. The
       wolf may crouch, ready to attack if necessary.
     * Suspicion – Pulling back of the ears shows a lupine is suspicious.
       In addition, the wolf narrows its eyes. The tail of a wolf that
       senses danger points straight out, parallel to the ground.
     * Relaxedness – A relaxed wolf's tail points straight down, and the
       wolf may rest sphinx-like or on its side. The wolf may also wag its
       tail. The further down the tail droops, the more relaxed the wolf
       is.
     * Tension – An aroused wolf's tail points straight out, and the wolf
       may crouch as if ready to spring.
     * Happiness – As dogs do, a lupine may wag its tail if it is in a
       joyful mood. The tongue may loll out of the mouth.
     * Hunting – A wolf that is hunting is tensed, and therefore the tail
       is horizontal and straight.
     * Playfulness – A playful lupine holds its tail high and wags it. The
       wolf may frolic and dance around, or bow by placing the front of
       its body down to the ground, while holding the rear high, sometimes
       wagged. This is reminiscent of the playful behaviour demonstrated
       by domestic dogs.

Howling

   Wolves howl for several reasons. Howling helps pack members keep in
   touch, allowing them to effectively communicate in thickly forested
   areas or over great distances. Furthermore, howling helps to summon
   pack members to a specific location. Howling can also serve as a
   declaration of territory, as portrayed by a dominant wolf's tendency to
   respond to a human imitation of a "rival" individual in an area that
   the wolf considers its own. This behaviour is also stimulated when a
   pack has something to protect, such as a fresh kill. As a rule of
   thumb, large packs will more readily draw attention to themselves than
   will smaller packs. Adjacent packs may respond to each others' howls,
   which can mean trouble for the smaller of the two. Thus, wolves tend to
   howl with great care.
   Howling adult wolf on glacial erratic at Little America Flats.
   Enlarge
   Howling adult wolf on glacial erratic at Little America Flats.

   Wolves will also howl for communal reasons. Some scientists speculate
   that such group sessions strengthen the wolves' social bonds and
   camaraderie— similar to community singing among humans. During such
   choral sessions, wolves will howl at different tones and varying
   pitches, which tends to prevent a listener from accurately estimating
   the number of wolves involved. This concealment of numbers makes a
   listening rival pack wary of what action to take. For example,
   confrontation could mean bad news if the rival pack gravely
   underestimates the howling pack's numbers.

   Observations of wolf packs suggest that howling occurs most often
   during the twilight hours, preceding the adults' departure to the hunt
   and following their return. Studies also show that wolves howl more
   frequently during the breeding season and subsequent rearing process.
   The pups themselves begin howling soon after emerging from their dens
   and can be provoked into howling sessions relatively easily over the
   following two months. Such indiscriminate howling usually has a
   communicative intent, and has no adverse consequences so early in a
   wolf's life. Howling becomes less indiscriminate as wolves learn to
   distinguish howling pack members from rival wolves.

Other vocalizations

   Growling, used in tandem with bared teeth, is the most visual and
   effective warning wolves use. Wolf growls have a distinct, deep,
   bass-like quality, and are used much of the time as a threat, though
   they are not always necessarily used for defense. Wolves will also
   growl at other wolves while being aggressively dominant.

   Wolves also bark, which they do when nervous or to warn other wolves of
   danger. Wolves bark very discreetly, and will not generally bark loudly
   or repeatedly as dogs do; rather, they use a low-key, breathy "whuf"
   sound to get attention immediately from other wolves. Wolves will also
   "bark-howl" by adding a brief howl to the end of a bark. Wolves
   bark-howl for the same reasons they normally bark. Actually, pups bark
   and bark-howl much more frequently than adults, using such
   vocalizations as cries for attention, care, or food.

   Wolves can also whimper, which they usually do only while submitting to
   other wolves. Wolf pups will whimper when they need a reassurance of
   security from their parents or other wolves.

Scent marking

   Wolves, like other canines, use scent marking to lay claim to anything
   from territory to fresh kills. Alpha wolves scent mark the most often,
   with males doing so more than females. The most widely used scent
   marker is urine. Male alpha wolves urine-mark objects using a
   raised-leg stance (all females squat) so as to enforce rank and
   territory. They will also use such marks to identify food caches and to
   claim kills on behalf of the whole pack. Defecation markers are used
   for the same purposes as urine marks, and serve as a more visual
   warning, as well. These types of scent markings are particularly useful
   for navigational purposes, keeping the pack from traversing the same
   terrain too often while also allowing each individual to be aware of
   the whereabouts of its pack members. Above all, though, scent marking
   is used to notify other wolves and packs that a given territory is
   occupied, and that they should therefore tread cautiously.

   Wolves have scent glands all over their bodies, including at the base
   of the tail, between toes, and in the eyes, genitalia, and skin.
   Pheromones secreted by these glands identify each individual wolf. A
   dominant wolf will "rub" his or her body against subordinate wolves to
   mark such individuals as being members of a particular pack. Wolves may
   also "paw" dirt to release pheromones in lieu of urine marking.

   Wolves' heavy reliance on odoriferous signals testifies greatly to
   their olfactory capabilities. Wolves can pick up any scent, including
   marks, from great distances, and can distinguish among them just as
   well or better than humans can distinguish other humans visually.

Social structure and hunting

The pack

   Wolves function as social predators and hunt in packs organized
   according to strict, rank-oriented social hierarchies. It was
   originally thought that this comparatively high level of social
   organization had more to do with hunting success, and while this still
   may be true to a certain extent, emerging theories suggest that the
   pack has less to do with hunting and more to do with reproductive
   success.

   The pack is led by the two individuals that sit atop the social
   hierarchy: the alpha male and the alpha female. The alpha pair (of whom
   only one may be the "top" alpha) has the greatest amount of social
   freedom compared to the rest of the pack, but they are not "leaders" in
   the human sense of the term. The alphas do not give the other wolves
   orders; rather, they simply have the most freedom in choosing where to
   go, what to do, and when to do it. Possessing strong instincts for
   fellowship, the rest of the pack usually follows.

   While most alpha pairs are monogamous with each other, there are
   exceptions. An alpha animal may preferentially mate with a
   lower-ranking animal, especially if the other alpha is closely related
   (a brother or sister, for example). The death of one alpha does not
   affect the status of the other alpha, who will quickly take another
   mate.

   Usually, only the alpha pair is able to successfully rear a litter of
   pups. Other wolves in a pack may breed, but will usually lack the
   resources required to raise the pups to maturity. All the wolves in the
   pack assist in raising wolf pups. Some mature individuals, usually
   females, may choose to stay in the original pack so as to reinforce it
   and help rear more pups. However, most will disperse, males
   particularly.

   The size of the pack may change over time and is controlled by several
   factors, including habitat, personalities of individual wolves within a
   pack, and food supply. Packs can contain 2–20 wolves, though an average
   pack consists of 6 or 7. New packs are formed when a wolf leaves its
   birth pack and claims a territory. Lone wolves searching for other
   individuals can travel very long distances seeking out suitable
   territories. Dispersing individuals must avoid the territories of other
   wolves because intruders on occupied territories are chased away or
   killed, a behaviour that may explain wolf "predation" of dogs. Most
   dogs, except perhaps large, specially bred attack dogs, do not stand
   much of a chance against a pack of wolves protecting its territory from
   an unwanted intrusion.

Hierarchy

   A wolf pack in Yellowstone National Park, with the alphas leading and
   the omega in the rear.
   Enlarge
   A wolf pack in Yellowstone National Park, with the alphas leading and
   the omega in the rear.

   The hierarchy, led by the alpha male and female, affects all activity
   in the pack to some extent. In most larger packs, there are two
   separate hierarchies in addition to an overbearing one: the first
   consists of the males, led by the alpha male, and the other consists of
   the females, led by the alpha female. In this situation, the alpha male
   usually assumes the "top" alpha position, though alpha females have
   been known to take control over entire packs in some cases. The male
   and female hierarchies are interdependent, and are maintained
   constantly by aggressive and elaborate displays of dominance and
   submission.

   After the alpha pair, there may also, especially in larger packs, be a
   beta wolf or wolves, a "second-in-command" to the alphas. Betas
   typically assume a more prominent role in assisting with the upbringing
   of the alpha pair's litter, often serving as surrogate mothers or
   fathers while the alpha pair is away. Beta wolves are the most likely
   to challenge their superiors for the role of the alpha, though some
   betas seem content with being second, and will sometimes even let lower
   ranking wolves leapfrog them for the position of alpha should
   circumstances necessitate such a happening, such as the death of the
   alpha. More ambitious beta wolves, however, will only wait so long
   before challenging for the top spot unless they choose to disperse and
   create their own pack instead.

   Loss of rank can happen gradually or suddenly. An older wolf may simply
   choose to give way when a motivated challenger presents itself,
   yielding its position without bloodshed. On the other hand, the
   challenged individual may choose to fight back, with varying degrees of
   intensity. While the majority of wolf aggression is non-damaging and
   ritualized, a high-stakes fight can easily result in injury for either
   or both parties. The loser of such a confrontation is frequently chased
   away from the pack or, rarely, may be killed as other aggressive wolves
   contribute to the insurgency. This kind of dominance encounter is more
   common during the mating season.

   Rank order within a pack is established and maintained through a series
   of ritualized fights and posturing best described as "ritual bluffing".
   Wolves prefer psychological warfare to physical confrontations, meaning
   that high-ranking status is based more on personality or attitude than
   on size or physical strength. Rank, who holds it, and how it is
   enforced varies widely between packs and between individual animals. In
   large packs full of easygoing wolves, or in a group of juvenile wolves,
   rank order may shift almost constantly, or even be circular (e.g.,
   animal A dominates animal B, who dominates animal C, who dominates
   animal A).

   In a more typical pack, however, only one wolf will assume the role of
   the omega: the lowest-ranking member of a pack. These individuals
   absorb the greatest amount of aggression from the rest of the pack, and
   may be subjected to different forms of truculence at any given point—
   anything from constant dominance from other pack members to inimical,
   physical harassment. Although this arrangement may seem objectionable
   after cursory analysis, the nature of pack dynamics demands that one
   wolf be at the bottom of the ranking order, and such individuals are
   perhaps better suited for constant displays of active and passive
   submission than they are for living alone. For wolves, camaraderie— no
   matter what the form— is preferable to solitude, and, indeed,
   submissive wolves tend to choose low rank over potential starvation.

Cooperative hunting and diet

   An American Bison standing its ground, thereby increasing its chance
   for survival.
   Enlarge
   An American Bison standing its ground, thereby increasing its chance
   for survival.

   Packs of wolves cooperatively hunt any large herbivores in their range.
   Pack hunting revolves around the chase, as wolves are able to run for
   long periods before relenting. It takes meticulous cooperation for a
   pack to take down a large prey animal, but the success rate of such
   chases is actually very low. Wolves, in the interest of saving energy,
   will only chase any one potential prey animal for the first thousand or
   so meters before giving up and trying again at a different time with a
   different prey. Hence, like most other pack species, wolves must hunt
   continually to sustain themselves. Solitary wolves depend more on
   smaller animals, capturing them by pouncing and pinning them to the
   ground with their front paws— a common technique among canids such as
   foxes and coyotes.

   Wolves' diets include, but are not limited to, elk, caribou, moose,
   deer, and other large ungulates. The American Bison is probably the
   largest animal wolves prey on, with bison exceeding a ton having been
   taken down by a pack. They also prey on rodents and small animals in a
   limited manner, as a typical adult wolf requires a minimum of 1.1 kg
   (2.5 lb) of food per day for sustenance, but approximately 2.2 kg (5
   lb) to reproduce successfully; however, this certainly doesn't mean
   that a wolf will get the chance to eat everyday. In fact, wolves rarely
   eat on a daily basis, so they compensate by eating up to a maximum of
   10 kg (22 lb) at a single sitting when they get the chance.

   When pursuing large prey, wolves generally attack from all angles,
   targeting the necks and sides of such animals. Wolf packs test large
   populations of prey species by inducing a chase, targeting less-fit
   individuals; such animals typically include the elderly, diseased, and
   young. Healthy animals may also succumb through circumstance or by
   chance. However, most healthy, fit individuals will stand their ground
   against wolves, increasing the possibility of injury for the wolves
   involved, which makes the weaker members of a species comparatively
   easier and safer to hunt.

   Like many other keystone predators, wolves are sensitive to
   fluctuations in prey abundance, making them likely to experience minor
   changes within their own populations as the abundance of their primary
   prey species gradually rises and drops over long periods of time. This
   balance between wolves and their prey prevents the mass starvation of
   all species involved.

Historical perceptions

   Original distribution of gray wolves by subspecies.
   Enlarge
   Original distribution of gray wolves by subspecies.
   Present distribution of gray wolves by subspecies.
   Enlarge
   Present distribution of gray wolves by subspecies.

   The relationship between humans and wolves has had a very long and
   turbulent history. Traditionally, humans have viewed wolves negatively,
   perceiving them to be dangerous or as nuisances to be destroyed – a
   perception now known to be extremely undeserved. European folklore
   exacerbated this negative image, which was brought over to North
   America with migrating Europeans. In brief, the gray wolf, which, at
   one point, could be found in any ecosystem on every continent in the
   Northern Hemisphere, was persistently one of the first species to go
   once a significant population of humans settled in a given area. As
   technology made the killing of wolves and other predators easier,
   simple control gave way to complete annihilation.

   Wolves are nevertheless considered in a positive light in some myths
   and legends, and many cultures use the word for wolf as a given name
   (Ulf, Ze'ev, etc.)

   Historically, unwarranted fear of the wolf has been responsible for
   most of the trouble the species has received, including why it was
   nearly hunted out of existence in the U.S. and Europe prior to the 20th
   century. However, ecological research conducted during the 20th century
   shed new light on wolves and other predators, specifically with regard
   to the critical role they play in maintaining the ecosystems to which
   they belong. As a result of this and other important factors, wolves
   have come to be viewed in a much more positive way.

   A general environmental awareness began to take root sometime in the
   middle of the 20th century that forced people to re-think former
   notions, including those regarding predators. In North America, people
   realized that in over one hundred years of documentation, there had
   been no verified human fatality caused by an attack from a healthy
   wolf. Wolves are actually naturally cautious and will almost always
   flee from humans, perhaps only carefully approaching a person out of
   curiosity. There are, however, some reported attacks in North America
   where it is thought that the wolves involved had become habituated to
   humans. Although attitudes have significantly changed, there are still
   many who hold more cautious views of the wolf.

Reintroduction

   In certain parts of the world, debate about wolf reintroduction is
   ongoing and oftentimes heated, both where reintroduction is being
   considered and where it has already occurred. Where wolves have been
   successfully reintroduced, as in the greater Yellowstone area and
   Idaho, reintroduction opponents continue to cite livestock predation,
   surplus killing, and economic hardships caused by wolves as reason why
   they should never have been reintroduced to begin with, as well as why
   they should be removed or severely reduced. Opponents in prospective
   areas echo these same concerns.

   However, what the Yellowstone and Idaho reintroductions demonstrate is
   how compromise can be used to satisfy relevant interests. These
   reintroductions were the culmination of over two decades of research
   and debate. Ultimately, the economic concerns of the local ranching
   industry, arguably the single best reason used against reintroduction,
   was dealt with when Defenders of Wildlife decided to establish a fund
   that would compensate ranchers for livestock lost to wolves, shifting
   the economic burden from industry to the wolf proponents themselves.
   The majority of the organizations opposing reintroduction relented
   their "no wolf, no way" stance when this crucial deal breaker was
   resolved.

   Today, there are over 300 wolves in the Greater Yellowstone Ecosystem
   and over 500 in Idaho. Both populations have long since met their
   recovery goals and the reintroduction experiment has been a resounding
   success. Still, lessons learned from this ordeal may yet prove useful
   where wolf reintroduction continues to create a sharp divide between
   industry and environmental interests, as it has in Arizona (where
   Mexican wolves were released beginning in 1998) and Scandinavia (where
   an inexplicable, isolated population has established itself over the
   past few decades). In some other Western and Central European
   countries, the debate will likely impair wolf reintroduction efforts
   where they are being considered, but, as history has validated,
   industry need not be ignored for a reintroduction effort to be
   successful.

Wolf hunting

Livestock predation

   As long as there is enough prey, wolves seem to avoid taking livestock,
   often ignoring them entirely. However, some wolves or packs can
   specialize in hunting livestock once the behaviour is learned despite
   natural prey abundance. In such situations, sheep are usually the most
   vulnerable, but horses and cattle are also at risk. Wolf-secure fences,
   relocation where applicable, and local wolf extermination are the only
   known methods to effectively stop livestock predation.

   Over several centuries, shepherds and dog breeders have used selective
   breeding to "create" large livestock-guarding dogs that can stand up to
   wolves preying on flocks. In the U.S., in light of the gray wolf and
   other large predators having recently been reintroduced to certain
   areas, the United States Department of Agriculture has been looking
   into the use of breeds such as the Akbash from Turkey, the Maremma from
   Italy, the Great Pyrenees from France, and the Kuvasz from Hungary,
   among others, to help limit wolf-livestock interactions.

   In some areas across the world, hunters or state officials will hunt
   wolves from helicopters or light planes to control populations (or for
   sport in some instances), citing it as the most effective way to
   control wolf numbers, given that traditional poisons are largely
   banned. The method is used where interactions between livestock and
   wolves are common, or where sport or subsistence hunters desire more
   game animals with less competition. Aerial hunting is seen as highly
   controversial. In areas where aerial hunting is used to limit
   livestock-wolf interactions or to boost populations of game animals,
   arguments against it are usually centered around whether or not the
   reasons behind such predator elimination are scientifically valid.

   In Alaska, for example, wolves are sometimes hunted from aircraft by
   sport hunters. The pilot will follow a wolfpack until the animals reach
   exhaustion and stop. The plane then lands and the hunters shoot the
   wolves. In some instances, the wolves are simply shot running, from the
   air, although this is technically illegal. Some regions of the state
   have no "bag limit", entitling hunters to shoot as many as they like.

   Other, non- or less-lethal methods of protecting livestock from wolves
   have been under development for the past decade. Such methods include
   rubber ammunition and use of guard animals.

Trapping and breeding for fur

   "How Wolves may be caught with a Snare," 15th century.
   Enlarge
   "How Wolves may be caught with a Snare," 15th century.

   Wolves are frequently trapped, in the areas where it is legal, using
   snares or leg hold traps. The economic value of wolf pelts is limited,
   so it is mainly a recreation activity. Wolf trapping has come under
   heavy fire from animal rights groups, who allege that unskilled
   trappers can create unnecessary suffering for the animal involved.
   Proponents counter that trapping, using the right tools and equipment,
   can be considered as humane as traditional hunting.
   A radio-collared wolf.
   Enlarge
   A radio-collared wolf.

   Wolves are also bred for their fur in a very few locations, but they
   are considered as a rather problematic animal to breed, and, combined
   with the low value of the pelt, most fur farms utilize other animals.

   Biologists may also trap wolves for research purposes. Darting and box
   traps are the tools of choice for such professionals, who often use
   these and similar techniques to fit wolves and other animals with
   collars holding radio transmitters and to check their health before
   releasing them. Use of such technology also allows them to keep track
   of population numbers and dispersal trends, among other things. Radio
   collars can also be used to monitor wolves when they come near
   livestock, and to identify a wolf or a pack that preys on livestock,
   allowing proper action to be prompter and more accurate.

Taxonomy

Classification and relation to the dog

   Much debate has occurred over the relationship between the wolf and the
   domestic dog. Most authorities see the wolf as the dog's direct
   ancestor, but others have postulated descent from the Golden Jackal.
   Because the canids have evolved recently and different canids
   interbreed readily, untangling the true relationships has presented
   difficulties. However, molecular systematics now indicate very strongly
   that domestic dogs and wolves are more closely related than either is
   to any other canid, and the domestic dog is now normally classified as
   a subspecies of the wolf: Canis lupus familiaris. The main differences
   between wolves and domestic dogs are that wolves have, on average, 30%
   larger brains, a better immune system, better sense of smell, and are
   generally much larger than domestic dogs.

   The classification of wolves and closely related creatures offers many
   challenges. Although taxonomists have proposed many species over the
   years, most types clearly do not comprise true species. Indeed, only a
   single wolf species may exist. While scientists have proposed a host of
   subspecies, wolf taxonomy at this level remains controversial. Further
   taxonomic modification will continue for years to come.

Subspecies of the wolf

   It was once believed there were up to 50 subspecies. However, the last
   decade has seen a new and widely accepted list that has been condensed
   to 13 living subspecies, 14 including the common dog, and 2 recently
   extinct subspecies. This takes into account the anatomy, distribution,
   and migration of various wolf colonies.
   Subspecies Classification Status Historic Range (see map)
   Arabian Wolf Canis lupus Arabs Critically endangered, declining Saudi
   Arabia, Yemen, Oman
   A very small subspecies. Typically blended brown or completely brown
   with a thin coat. Hunted regularly as a nuisance animal, though rarely
   encountered.
   Arctic Wolf Canis lupus arctos Stable Canadian Arctic, Greenland
   An average-sized subspecies. Almost exclusively white or creamy white
   with a thick coat. Hunted legally, though rarely encountered.
   Caspian Sea Wolf Canis lupus cubanensis Endangered, declining Between
   the Caspian and Black seas
   A smaller subspecies. Hunted as a nuisance animal.
   Domestic Dog Canis lupus familiaris Stable Worldwide
   Typically, a smaller subspecies, with 20% smaller brains, poorer immune
   system, and poorer sense of smell. Maintained as pets, although some
   small feral populations do exist. Raised for their meat in some parts
   of the world.
   Eastern Timber Wolf Canis lupus lycaon At risk Southeastern Canada,
   Eastern United States
   A larger subspecies. Full canine colour spectrum represented, though
   blended pelages predominate. First subspecies to be recognized in North
   America. Hunted legally in parts of Canada.
   Egyptian Wolf Canis lupus lupaster Critically endangered, unknown Far
   Northern Africa
   A smaller subspecies. Usually a grizzled or tinged gray or brown.
   Lanky. Very rarely encountered.
   Eurasian Wolf Canis lupus lupus Stable Western Europe, Scandinavia,
   Russia, China, Mongolia, Himalaya Mountains
   An average-sized subspecies. Generally short, blended gray fur. Largest
   range among wolf subspecies. Most common wolf subspecies in Europe and
   Asia. Population roughly 100,000. Hunted legally in some places,
   protected in others.
   Great Plains Wolf Canis lupus nubilus Stable Southern Rocky Mountains,
   Midwestern United States, Eastern and Northeastern Canada, far
   Southwestern Canada, and Southeastern Alaska
   An average-sized subspecies. Usually gray, black, buff, or reddish. The
   most common subspecies in the contiguous U.S. Hunted legally in parts
   of Canada.
   Hokkaido Wolf Canis lupus hattai Extinct Japanese island of Hokkaido
   A smaller subspecies. Became extinct in 1889 as a result of poisoning
   campaigns.
   Honshu Wolf Canis lupus hodophilax Extinct Japanese islands of Honshu,
   Shikoku, and Kyushu
   A very small subspecies. Became extinct in 1905 from a combination of
   rabies and human eradication efforts.
   Indian Wolf Canis lupus pallipes Endangered, declining Iran,
   Afghanistan, Pakistan, India
   A very small subspecies. Typically tawny, buff, or reddish with a very
   short, dense coat. Hunted as a nuisance animal.
   Italian Wolf Canis lupus italicus Endangered Italian peninsula
   An average-sized subspecies. Full canine colour spectrum represented.
   Occupy comparatively smaller territories. Protected.
   Mackenzie Valley Wolf Canis lupus occidentalis Stable Alaska, Northern
   Rockies, Western and Central Canada
   A very large subspecies. Usually black or a blended gray or brown, but
   full colour spectrum represented. This subspecies was reintroduced to
   Yellowstone National Park and Idaho starting in 1995. Hunted legally in
   Alaska and parts of Canada. Protected in the contiguous states.
   Mexican Wolf Canis lupus baileyi Critically endangered Central Mexico,
   Western Texas, Southern New Mexico and Arizona
   A smaller subspecies. Usually tawny brown or rusty in colour.
   Reintroduced to Arizona starting in 1998. Current wild population
   35-50. Current captive population 300. Protected.
   Russian Wolf Canis lupus communis Stable, declining Central Russia
   A very large subspecies. Hunted legally.
   Tundra Wolf Canis lupus albus Stable Northern Russia, Siberia
   A larger subspecies. Typically creamy white or gray, though full
   spectrum is represented. Hunted legally.
   Retrieved from " http://en.wikipedia.org/wiki/Gray_Wolf"
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   with only minor checks and changes (see www.wikipedia.org for details
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