Gray Wolf

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Gray Wolf Fossil range: Late Pleistocene - Recent
Eurasian Wolf (C. lupus lupus)
Conservation status
Least Concern [1]
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Canidae Genus: Canis Species: C. lupus
Binomial name
Canis lupus Linnaeus, 1758
Range map. Green, present; red, former.

The Gray Wolf (Canis lupus; also spelled Grey Wolf, see spelling differences; also known as Timber Wolf or Wolf) is a mammal of the order Carnivora and one of three species called 'wolf'. The Gray Wolf, along with the Coyote (Canis latrans), the Golden Jackal (Canis aureus) and the domestic dog (Canis lupus familiaris), is a member of the small genus Canis; the domestic dog (Canis lupus familiaris), in fact, shares a common ancestry with the Gray Wolf, as evidenced by DNA sequencing and studies of genetic drift.^[2] The Gray Wolf is the largest of its genus: its shoulder height ranges from 0.6–0.9 meters (26–36 inches), and weight from 32–62 kilograms (70–135 pounds). Its bulky two-layered coat can be gray, gray-brown, white, red, brown or black, or shades of all of these colors.

The Gray Wolf was once abundant over much of North America and Eurasia. However, as a result of habitat depredations and hunting, it now inhabits a very limited portion of its former range. The species is generally listed as endangered or threatened, although it is listed as of least concern for extinction for some regions, including the Continental United States.^[3]

The Gray Wolf forms an important part of the ecosystem as a keystone predator. The Gray Wolf's habitat spans temperate forests, mountains, tundra, taiga, and grasslands; and reflects its adaptability as a species. In much of the world, though not in the north, it is listed as endangered. It is still hunted in many areas of the world for its perceived threat to livestock, as well as for sport.

Contents 1 Description and life cycle 1.1 Physical characteristics 1.2 Courtship and mating 1.3 Reproduction 1.4 Mortality 2 Taxonomy 2.1 Classification and relation to the dog 2.2 Subspecies 3 Behavior 3.1 Body language 3.2 Howling 3.3 Other vocalizations 3.4 Scent marking 3.5 Social structure 3.5.1 Hierarchy 3.6 Diet and hunting 4 Relationships with other predators 5 Historical perceptions 5.1 In folklore and mythology 5.1.1 Werewolves 5.2 Modern perceptions 6 Reintroduction 7 Wolf hunting 7.1 Livestock predation 7.2 Trapping and breeding for fur 8 Media 9 See also 10 Notes and references 11 External links

Description and life cycle

Physical characteristics

The weight and size of the Gray Wolf can vary greatly worldwide, and tend to increase proportionally with latitude, as predicted by Bergmann's Rule. In general, height varies from 0.6–0.9 meters (26–36 inches) at the shoulder, and weight from 32–62 kilograms (70–135 pounds), which together make the Gray Wolf the largest of all wild canids.^[4] Although rarely encountered, extreme specimens of more than 77 kg (170 lb) have been recorded in Alaska and Canada;^[5] the heaviest wild wolf on record, which was killed in Alaska in 1939, was 80 kg (175 lb).^[6] The smallest wolves come from the Arabian Wolf subspecies, the females of which may weigh as little as 10 kg (22 lb) at maturity. Females in a given population typically weigh about 20% less than their male counterparts.^[7] Wolves can measure anywhere from 1.3–2 meters (4.5–6.5 feet) from nose to the tip of the tail, which itself accounts for approximately one quarter of overall body length.^[8]

Wolves are built for stamina, possessing features ideal for long-distance travel. Their narrow chests and powerful backs and legs facilitate efficient locomotion. They are capable of covering several miles trotting at about a pace of 10 km/h (6 mph), and have been known to reach speeds approaching 65 km/h (40 mph) during a chase.^[9] While thus sprinting, wolves can cover up to 5 meters (16 ft) per bound.^[10]

Wolf paws are able to tread easily on 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, which, with the relative largeness of their feet, helps them to distribute their weight well on snowy surfaces. The front paws are larger than the hind paws, and have a fifth digit, the dewclaw, that is absent on hind paws.^[11] Bristled hairs and blunt claws enhance grip on slippery surfaces, and special blood vessels keep paw pads from freezing.^[12] Scent glands located between a wolf's toes leave trace chemical markers behind, helping the wolf to effectively navigate over large expanses while concurrently keeping others informed of its whereabouts.^[12]

A wolf sometimes seems heavier than it actually is because of 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 the wolf. The undercoat is shed in the form of large tufts of fur in late spring or early summer (with yearly variations). A wolf will often rub against objects such as rocks and branches to encourage the loose fur to fall out. The undercoat is usually gray regardless of the outer coat's appearance. 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, running 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 color (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 color 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. It is often thought that the coloration of the wolf's pelage serves the purpose of camouflage. This is not entirely correct, as some scientists have noted that the blended colors are more to do with emphasizing gestures, much like eye shadow or lipstick on humans.^[13]

At birth, wolf pups tend to have darker fur and blue irises that will change to a yellow-gold or orange color when the pups are 8–16 weeks old.^[14] Though extremely unusual, it is possible for an adult wolf to retain its blue-colored irises.^[15]

Wolves' long, powerful muzzles help distinguish them from coyotes and golden jackals, which have more narrow, pointed muzzles; and from dogs, which generally have shorter muzzles. Wolves also differ in certain skull dimensions, having a smaller orbital angle, for example, than dogs (>53 degrees for dogs compared with <45 degrees for wolves) and a comparatively larger cerebral capacity.^[16] 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.^[17] 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. Capable of delivering up to 1500 lb/sq. inch (~10 MPa) of pressure, a wolf's teeth are its main weapons as well as its primary tools.^[6] Therefore, any injury to the jaw line or teeth could devastate a wolf, dooming it to starvation or incapacity.

Courtship and mating

Usually, the instinct to reproduce 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 of wolves who have reached sexual maturity in the previous breeding season. It takes two such dispersals from two packs for the process to take place, for dispersing wolves from the same maternal pack tend not to mate.^[18] Once two dispersing wolves meet and begin traveling together, they immediately begin the process of seeking out territory, preferably in time for the next mating season. The bond that forms between these wolves often lasts until one of them dies.^[19]

During the mating season, breeding wolves become very affectionate with one another in anticipation of the female's ovulation cycle. The pack tension rises as each mature wolf feels urged to mate. During this time, in fact, the alpha male and alpha female may be forced to aggressively prevent other wolves from mating with one another.^[18] Under normal circumstances, a pack can only support one litter per year; so the dominance of the alpha wolves is beneficial in the long run.^{[specify][18]}

When the alpha female goes into estrus (which occurs once per year and lasts 5–14 days),^[20] she and her mate will spend an extended time in seclusion. Pheromones in the female's urine and the swelling of her vulva make known to the male that the female is in heat. The female is unreceptive for the first few days of estrus, during which time she sheds the lining of her uterus; but when she begins ovulating again, the two wolves mate.

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 to 30 minutes, during which the male will ejaculate multiple times.^[21][22] 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.^[22] The mating ritual is repeated many times throughout the female's brief ovulation period, which occurs once per year per female—unlike female dogs, whose estrus usually occurs twice per year.

Reproduction

Normally, only the alpha pair of the pack breeds (this is a kind of organization also found in other pack-hunting canids, including the Dhole and the African Hunting Dog). Mating occurs between January and April—the higher the latitude, the later it occurs.^[19] A pack usually produces a single litter, unless the alpha male mates with one or more subordinate females. Under normal circumstances, the alpha female tries to prevent this during mating season by dominating the other females and keeping them away from the alpha male.

The gestation period lasts 60–63 days. The pups, at a weight of 0.5 kg (1 lb), are born blind, deaf, and completely dependent on their mother.^[19][4] There are 1 to 14 pups per litter; the average litter size is about 4 to 6.^[23] Pups reside in the den and stay there until they reach about three 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.^[12] 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.^[19]

After two months, the restless pups will be moved to a rendezvous site, where they can safely stay while most of the adults go out to hunt. One or two adults 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, and will receive priority on anything killed, despite their low ranks. The pups tag along as observers until about 8 months, when they are large enough to actively participate. The fighting over eating privileges results in a secondary ranking being formed among them, which allows them to practice the dominance/submission rituals essential to their later survival within packs.^[19] Wolves typically reach sexual maturity after two or three years, when many of them will be compelled to leave their birth packs and seek out mates and their own territories.^[19][24]

Mortality

Wolves that reach maturity generally live 6 to 8 years in the wild, although in captivity they can live to twice that age.^[23] High mortality rates give them a low overall life expectancy. Pups die when food is scarce; they can also fall prey to predators such as bears, or, less often, coyotes, foxes, or other wolves. The most significant causes of mortality for grown wolves are hunting and poaching, car accidents, and wounds inflicted while hunting prey. Although adult wolves may occasionally be killed by other predators, rival wolf packs are often their most dangerous non-human enemy. A study on wolf mortality came up with results indicating that 14% to 65% of wolf deaths were due to other wolves.^[25] Wolves are susceptible to the same infections that affect domestic dogs, such as mange, heartworm, rabies, parvovirus and canine distemper. Epidemics of these can drastically reduce the population in an area.

Taxonomy

The Gray Wolf was one of the many species originally described by Linnaeus in his 18th century work, Systema Naturae, and it still bears its original name of Canis lupus;^[26] the generic name is derived from the Latin Canis for "dog", and the specific one from lupus for "wolf".^[27] Classifying wolves and closely related creatures can be challenging. Although taxonomists have proposed many species over the years, most types clearly do not constitute true species; indeed, only a single wolf species may exist. Although scientists have proposed a host of subspecies, wolf taxonomy at this level remains controversial.^[28] Taxonomic modification will likely continue for years to come.

Although the origins of the Gray Wolf are still under debate, current theories propose that the species first evolved in South East Asia during the Pleistocene epoch. DNA analysis from the cell's mitochondria on Asiatic subspecies have allowed scientists to put a time to the point at which the wolf lineage originated. The rate of changes observed in the DNA sequence dates the Asian lineage to about 800,000 years, as opposed to European and North American bloodlines which stretch back to 150,000 years.^[29] The wolf likely crossed into North America from the Old World via the Bering land bridge (that once joined Alaska and Siberia) and traveled south of the ice sheets prior to the last glacial maximum 18,000 years ago.^[30]

Classification and relation to the dog

The Gray Wolf is a member of the small genus Canis, which comprises between 7 and 10 species. It is one of six species termed 'wolf', the others being the Red Wolf (Canis rufus), the Indian Wolf (Canis indica), the Himalayan wolf (Canis himalayaensis), the Eastern Canadian Wolf (Canis lycaon) and the Ethiopian Wolf (Canis simensis). Also related are the Coyote (Canis latrans), the Golden Jackal (Canis aureus) and the domestic dog.

Much debate has centered on the relationship between the wolf and the domestic dog; most authorities seeing the wolf as the dog's direct ancestor, but others postulating descent from the Golden Jackal. Because the canids have evolved recently and different canids interbreed readily, untangling the true relationships has been difficult. But 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.^[31]

Subspecies

At one stage there were up to 50 subspecies recognized. However, consensus has condensed this to 15 extant subspecies including the common dog and dingo, and 2 more recently extinct. This takes into account the anatomy, distribution, and migration of various wolf colonies. It should be noted however that not all extinct subspecies owed their extermination to human predation; the Newfoundland Wolf, for example, is theorized to have vanished after relocating Westwards and breeding itself out by mating with the local Mackenzie Valley Wolf populations.^[13]

Subspecies	Classification	Status	Historic Range (see map)
Arabian Wolf	Canis lupus Arabs	Critically endangered, declining	Israel, 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.
Dingo	Canis lupus dingo	Vulnerable (pure breed)	Australia & southeast Asia
	Hunted as a nuisance animal. Pure breed declining from interbreeding with the Domestic Dog.
Domestic Dog	Canis lupus familiaris	Stable	Worldwide
	Typically, a smaller subspecies, with 20% smaller brains, more feeble 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 color 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, probably extinct	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 to large-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.
Iberian Wolf	Canis lupus signatus	Stable	North Portugal, North-Western Spain
	An average-sized subspecies. Distinct for its black markings and rusty red pelage. Conservation dependant.
Italian Wolf	Canis lupus italicus	Endangered	Italy, Switzerland, France
	An average-sized subspecies. Full canine color 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 color 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 color. Reintroduced to Arizona starting in 1998. Current wild population 35–50. Current captive population 300. Protected.
Newfoundland Wolf	Canis lupus beothucus	Extinct	Newfoundland
	A medium-sized subspecies. Almost pure white. Extinct around 1911.
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 gray, with mixes of black, rust and silver, though full spectrum is represented. Hunted legally.
Vancouver Island Wolf	Canis lupus crassodon	Endangered	Vancouver Island
	A medium-sized subspecies. Ranges in color from grayish-black to white.

Behavior

Body language

See also: Dog communication

Wolves can communicate visually through a wide variety of expressions and moods ranging from subtle signals, such as a slight shift in weight, to more obvious ones, such as rolling on their backs to indicate complete submission.^[32]

• 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 vertically and curled toward the back. This display asserts the wolf's rank to others in the pack. A dominant wolf 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) – During 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 posture is often accompanied by whimpering.
• Anger – An angry wolf'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 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 wolf is suspicious. The wolf also 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 wolf may wag its tail if 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 wolf 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 resembles the playful behavior of domestic dogs.

Howling

Howling helps pack members keep in touch, allowing them to communicate effectively in thickly forested areas or over great distances. Howling also helps to call pack members to a specific location. Howling can also serve as a declaration of territory, as shown in a dominant wolf's tendency to respond to a human imitation of a "rival" wolf in an area the wolf considers its own. This behavior is 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. Wolves therefore tend to howl with great care.^[33]

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.^[33] During such choral sessions, wolves will howl at different tones and varying pitches, making it difficult to estimate the number of wolves involved. This confusion of numbers makes a listening rival pack wary of what action to take. For example, confrontation could be disastrous if the rival pack gravely underestimates the howling pack's numbers. A wolf's howl may be heard from up to ten miles away, depending on weather conditions.

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 easily over the following two months. Such indiscriminate howling usually is intended for communication, and does not harm the wolf so early in its life.^[33] Howling becomes less indiscriminate as wolves learn to distinguish howling pack members from rival wolves.

The Arabian and Indian subspecies are unusual as they are not known to howl.^[13][34]

Other vocalizations

Growling, while teeth are bared, is the most visual and effective warning wolves use. Wolf growls have a distinct, deep, bass-like quality, and are often used to threaten rivals, though not necessarily to defend themselves. Wolves also growl at other wolves while being aggressively dominant.

Wolves bark when nervous or when they want 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 immediately get attention of other wolves. Wolves also "bark-howl" by adding a brief howl to the end of a bark. Wolves bark-howl for the same reasons they normally bark. Generally, pups bark and bark-howl much more frequently than adults, using these vocalizations to cry for attention, care, or food.

A lesser known sound is the rally. Wolves will gather as a group and, amidst much tail-wagging and muzzle licking, emit a high-pitched wailing noise interspersed with something similar (but not the same as) a bark. Rallying is often a display of submission to an alpha of the pack by the other wolves.^[35]

Wolves can also whimper, usually when submitting to other wolves. Wolf pups whimper when they need the 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.^[36] Alpha wolves use scent mark the most often; males do so more than females. The most widely used scent marker is urine. Male and female alpha wolves urine-mark objects with a raised-leg stance (all other pack members squat) to enforce rank and territory. They also use marks to identify food caches and to claim kills on behalf of the pack. Defecation markers are used for the same purposes as urine marks, and serve as a more visual warning, as well.^[36] Defecation markers are particularly useful for navigation, keeping the pack from traversing the same terrain too often and also allowing each wolf to be aware of the whereabouts of its pack members. Above all, though, scent marking is used to inform other wolves and packs that a certain 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.^[36] Pheromones secreted by these glands identify each individual wolf. A dominant wolf will "rub" its body against subordinate wolves to mark such wolves as being members of a particular pack. Wolves may also "paw" dirt to release pheromones instead of urine marking.^[37]

Wolves' heavy reliance on odoriferous signals testifies greatly to their olfactory capabilities. Wolves can detect virtually any scent, including marks, from great distances, and can distinguish among them as well or better than humans can distinguish other humans visually.^{[citation needed]}

Social structure

Wolves function as social predators and hunt in packs organized according to strict, rank-oriented social hierarchies.^[19] It is thought that this comparatively high level of social organization had much to do with hunting success. Emerging theories also suggest, however, 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 has the greatest amount of social freedom compared to the rest of the pack. Although they are not "leaders" in the human sense of the term, they help to resolve any disputes within the pack, have the greatest amount of control over resources, such as food, and most importantly, hold the pack together. Possessing strong instincts for fellowship, the rest of the pack usually follows.

While most alpha pairs are monogamous, there are exceptions.^[38] 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.^[19]

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.^[specify] 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.

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 from 2 to 20 wolves, though an average pack consists of about 8.^[39] New packs are formed when a wolf leaves its birth pack, finds a mate, 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. It is taboo for one wolf to travel into another wolf's territory unless invited. 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 intrusion.

Wolves acting unusually within the pack, such as epileptic pups or thrashing adults crippled by a trap or a gunshot are usually killed by their own pack members.^[13]

Hierarchy

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.^[12] In this situation, the alpha male was originally assumed to be the "top" alpha, but biologists have since concluded that alpha females can and do take control over entire packs.^{[citation needed]} 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 contending for alpha position 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 not injurious and is ritualized, a high-stakes fight can easily result in injury for either or both parties. Deaths do occur, as the average alpha male wolf may kill two to four wolves in his lifetime.^[40] 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. These confrontations are 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 (for instance, animal A dominates animal B, who dominates animal C, who dominates animal A).

In a more typical pack, only one wolf will assume the role of the omega: the lowest-ranking member of a pack.^[36] Omegas receive the most aggression from the rest of the pack, and may be subjected to truculence at any time—anything from constant dominance from other pack members to inimical, physical harassment. Although this arrangement may seem objectionable, 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. Despite the aggression they are subject to and being last to eat, omega wolves have also been observed to often be the most playful wolves in the group, often enticing all of the members of a pack into chasing games and other forms of play.

One theory about the domestication of the dog is that it occurred when certain wolves of a suitable temperament joined bands of human hunter-gatherers due to their organizational similarities with wolf packs.^{[verification needed]}

Diet and hunting

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 careful cooperation for a pack to take down large prey, and the rate of success for such chases is very low. Wolves, in the interest of saving energy, will only chase one potential prey for the first thousand or so meters before giving up and trying at a different time against a different prey.^[41] Therefore, like most other pack species, wolves must hunt continually to sustain themselves. Solitary wolves depend more on smaller animals, which they capture by pouncing and pinning them, with their front paws, to the ground—this technique is also common among other canids such as foxes and coyotes.

Wolves' diet includes, but is not limited to, deer, caribou, moose, yak, and other large ungulates. The American Bison is probably the largest animal wolves prey on; bison weighing more than a ton have been taken down by a pack. They also prey on rodents, small animals, and other canids like foxes and coyotes in a limited manner,^[specify] for a typical adult wolf requires a minimum of 1.1 kg (2.5 lb) of food each day for sustenance, and approximately 2.2 kg (5 lb) to reproduce successfully.^[23] Wolves do not always have the chance to eat each day; in fact, wolves rarely eat on a daily basis, but instead compensate by eating up to a maximum of 10 kg (22 lb) at a time.^[23]

When pursuing large prey, wolves generally attack from all angles, targeting the necks and sides of their prey. Wolf packs test large populations of prey species by initiating a chase, targeting less-fit prey; such animals typically include the elderly, diseased, and young.^[24] Healthy animals may also succumb through circumstance. However, most healthy, fit individuals will stand their ground against wolves, increasing the possibility of injury to the preying wolves;^[specify] thus the weaker members of a species are easier and safer to hunt.

Like many other keystone predators, wolves are sensitive to fluctuations in the abundance of prey; they are likely to have minor changes in their 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 both predator and prey.

Relationships with other predators

One of the most well researched wolf/predator interactions is that involving the Coyote. Wolves are generally intolerant of Coyotes in their territory, seeing them as competitors for food and as threats to their cubs. In fact, two years after their re-introduction to the Yellowstone National Park, the wolves were responsible for a near 50% drop in Coyote populations through both competition and predation. Though smaller in size, Coyotes are usually swift enough to escape the jaws of Wolves and on some occasions, have even been known to gang up on them.^[42] Near identical interactions have been observed in Greece between Wolves and Golden Jackals.^[43]

The Cougar is another predator encountered by the Gray Wolf in North America. As with the Coyote, the Gray Wolf is usually hostile toward the big cats and will kill kittens if given the opportunity. The wolf's relation to adults is more complex. A pack often takes advantage of cougars, stealing kills and sometimes killing mature adults. Interactions between solitary wolves and cougars are rarer, but the two species have killed each other.^[44] National Park Service cougar specialist Kerry Murphy stated that the cougar usually is at an advantage on a one to one basis, considering it can effectively use its claws, as well as its teeth, unlike the wolf which relies solely on its teeth. Yellowstone officials have reported that attacks between cougars and wolves are not uncommon. Multiple incidents of cougars taking wolves and vice versa have been recorded in Yellowstone national park. However, researchers in Montana have found wolves regularly kill cougars in the area, though they did not specify whether or not this was a pack situation.^[45]

Brown bears are among the few competitors wolves encounter in both Eurasia and North America, while the American Black Bear is encountered solely in America. The majority of interactions between wolves and bears usually amount to nothing more than mutual avoidance. Serious confrontations depend on a variety of variables, though the most common factor is defence of food and young. Bears will use their superior size to intimidate wolves from their kills and when sufficiently hungry, will raid wolf dens. Wolves in turn have been observed killing bear cubs, to the extent of even driving off the defending mother bears. Deaths in wolf/bear skirmishes are however considered very rare occurrences, the individual power of the bear and the collective strength of the wolf pack usually being sufficient deterrents to both sides.^[46]

In Russia, the Gray Wolf's status as an apex predator is competed by the Siberian Tiger. Siberian Tigers have been known to prey on Wolves and the two species compete for the limited prey base.^[47] Studies have shown that Gray Wolf populations generally decrease in areas inhabited by the Siberian Tiger.^[48]

In some Middle Eastern countries, the Gray Wolf will sometimes encounter the Striped Hyena, mostly in disputes over carcasses. Though not as powerful individually, the Gray Wolf's social nature usually puts the more solitary hyena at a disadvantage in confrontations.^[49]

Of all the wolf's interspecific conflicts, none has contributed more to the species negative imagery than that against the domestic dog. It has been theorized that wolves treat dogs as they would any other competitor, which explains why the majority of attacked pets are usually hunting dogs unwittingly entering the wolf's turf.^[50] In some instances, Wolves have displayed an uncharacteristic fearlessness of humans and buildings when attacking dogs, to an extent where they have to be beaten off or killed.^[51] Few dogs can hold their own against lone wolves, let alone wolf packs. Notable exceptions include specially bred Livestock guardian dogs, though their primary function has more to do with intimidating the wolves rather than fighting them.^[52] Conversely, wolves have on occasion been known to mate with dogs to produce mix-breed offspring known as wolfdogs. Although there has been concern that European wolf populations may have extensively hybridized with stray dogs, truly significant genetic contamination of dog genes into wild wolf populations has not been confirmed. The extent of physical and behavioural differences between dogs and wolves is usually great enough to ensure that mating is unlikely and hybrid offspring rarely survive to reproduce in the wild.^[53]

Historical perceptions

Main articles: Attitudes toward wolves and List of fatal wolf attacks

In folklore and mythology

Traditionally humans held a distasteful view of wolves, a creature they feared. It was also often accentuated in European folklore beginning in the Christian era. Settlers brought this view with them as they settled North America. The Gray Wolf, once found in every ecosystem across the Northern Hemisphere, was one of the first species to be culled by settlers. As technology made the killing of wolves and predators easier, humans began to overhunt wolves and cause their numbers to dwindle significantly.

Wolves are nevertheless portrayed positively in some myths and legends, and many languages have names meaning "wolf". Some examples include, for instance: Scandinavian Ulf, Albanian "Ujk", Hebrew Ze'ev, Serbian Vuk, Bulgarian Vǎlko,

In Norse mythology, Fenrir or Fenrisulfr is a gigantic wolf, the son of Loki and the giantess Angrboða. Fenrir is bound by the gods, but is ultimately destined to grow too large for his bonds and devour Odin during the course of Ragnarök. At that time he will have grown so large that his upper jaw touches the sky while his lower touches the earth when he gapes. He will be slain by Odin's son, Viðarr, who will either stab him in the heart or rip his jaws asunder according to different accounts.

In Central Asian nations such as that of Turkic peoples and Mongols, the wolf is a revered animal. The shamanic Turkic peoples even believed they were descendants of wolves in Turkic legends. The legend of Asena is an old Turkic myth that tells of how the Turkic people were created. In Northern China a small Turkic village was raided by Chinese soldiers, but one small baby was left behind. An old she-wolf with a sky-blue mane named Asena found the baby and nursed him, then the she-wolf gave birth to half wolf, half human cubs therefore the Turkic people were born. Also in Turkic mythology it is believed that a Gray Wolf showed the Turks the way out of their legendary homeland Ergenekon, which allowed them to spread and conquer their neighbours.^[54][55]

Werewolves

Main article: Werewolf

Stories of werewolves can be found in virtually all European countries; these date back from Ancient Greek legend of Lycaon, who in one story was transformed into a wolf as a result of eating human flesh, and the writings of the Roman scholar, Pliny the Elder.^[56]

Modern perceptions

Historically, the fear of wolves has been responsible for most of the species' trouble, including its near extinction in Europe and the United States during the 20th century. Ecological research in the 20th century has shed new light on wolves and other predators, specifically with regard to their critical role in maintaining ecosystems to which they belong. This information has led to a more positive portrayal.

A general increase in environmental awareness began to take root sometime in the middle of the 20th century and forced people to rethink 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 fatalities caused by an attack from a healthy wolf.^[57][58] 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 reports of possible wolf attacks in North America that people assumed happen on a regular basis.^[59] Although attitudes have significantly changed, there are still many who hold more cautious views of the wolf. In fact, there are many Americans who believe that the criteria a wolf attack has to fill (in order to be labelled as an actual attack) are unreasonable and that they ignore Indian and Eskimo oral history which confirms that Native Americans were in fact on occasion attacked by wolves long before the arrival of European settlers.^[13]

Though wolf attacks in North America are very rare, they do occur far more frequently in the Old World, particularly Asia. These attacks usually occur in rural, poverty stricken areas where the people have no firearms or other effective means of predator control. A recent Fennoscandian study on historical wolf attacks occurring in the 18th–19th centuries indicated that victims were almost entirely children under the age of 12, with 85% of the attacks occurring when an adult was not present. In the few cases when an adult was killed, it was almost always a woman. In nearly all cases, only a single victim was injured in each attack, although the victim was with 2–3 other people in a few cases. This contrasts dramatically with the pattern seen in attacks by rabid wolves, where up to 40 people could be bitten in the same attack.^[60] It should also be noted that some recorded attacks occurred over a period of months or even years. This makes the likelihood of rabies infected perpetrators unlikely, considering that death usually occurs within 2–10 days after the initial symptoms.

A hypothesis as to why wolves in Europe and Asia act more aggressively toward humans than those in North America is that in the past, Old World wolf hunting was mostly an activity for the nobility, whereas American wolf hunts were partaken by ordinary citizens, nearly all of them possessing firearms. This difference could have caused American wolves to be more fearful of humans, making them less willing to venture into settled areas.^[61]

Reintroduction

Main article: Wolf reintroduction

In certain parts of the world, debate about wolf reintroduction is ongoing and often 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.^[62] 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.^[63] The majority of the organizations opposing reintroduction relented their "no wolf, no way" stance when this crucial deal breaker was resolved.

As of 2005, there are over 450 wolves in the Greater Yellowstone Ecosystem and over 1,000 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 the Mexican Wolf was released beginning in 1998). 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.

Though many hunters, prior to and even after reintroduction, claimed that wolves would wipe out entire populations of elk, deer and other ungulates, most ecosystems where wolves have been reintroduced have actually become much healthier than they were before. Since Wolves have arrived, the food chain within the Yellowstone ecosystem has been re-ordered to deliver a banquet that favors a more varied array of species. Prior to wolves, high numbers of elk were linked to declines in aspen and willow communities, which negatively affected beaver and moose. Pre-wolf, coyote numbers swelled, affecting small rodent populations, foxes, and the production of pronghorn antelope. Pre-wolf scavengers had slimmer pickings. Today with wolves taking elk, reducing their numbers, and leaving more carcasses on the landscape, grizzlies and wolverines have easier access to more meat, meaning a better chance for larger litters of cubs and pups. Coyote numbers have been significantly reduced, meaning more mice and pocket gophers for foxes and avian predators like hawks and eagles.^[64] Wolves play an undeniably important role in the environment and through education organizations some people may be slowly getting the message that they are vital. In addition, reports have been published placing the value of revenue from wolf-watching as upward of US$25 million.

Wolf hunting

Main article: Wolf hunting

Livestock predation

As long as there is enough prey, wolves seem to avoid taking livestock, often ignoring them entirely.^[65] However, some wolves or packs can specialize in hunting livestock once the behavior 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 sometimes hunting wolves 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.^[66] 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.

While wolf predation on livestock does happen, loss of livestock by wolves makes up only a small percentage of total losses in North America. Since the state of Montana began recording livestock losses due to wolves back in 1987, only 1,200 sheep and cattle have been killed. 1,200 killings in twenty years is not very significant when in the greater Yellowstone region 8,300 cattle and 13,000 sheep die from natural causes. According to the International Wolf Center, a Minnesota-based organization:

To put depredation in perspective, in 1986 the wolf population was at about 1,300–1,400, there were an estimated 232,000 cattle and 16,000 sheep in Minnesota's wolf range. During that year 26 cattle, about 0.01% of the cattle available, and 13 sheep, around 0.08% of the sheep available, were verified as being killed by wolves. Similarly, in 1996 an estimated 68,000 households owned dogs in wolf range and only 10, approximately 0.00015% of the households, experienced wolf depredation.

– Wolf Depredation, International Wolf Center, Teaching the World about Wolves^[67]

Furthermore, Jim Dutcher, a film maker who raised a captive wolf pack observed that wolves are very reluctant to try meat that they have not eaten or seen another wolf eat before possibly explaining why livestock depredation is unlikely except for in cases of desperation.^[68]

The results however differ in some Old World countries. Greece for example reports that between April 1989 and June 1991, 21000 sheep and goats plus 2729 cattle were killed. In 1998 it was 5894 sheep and goats, 880 cattle and very few horses. ^[43] A study on livestock predation taken in Tibet showed that the wolf was the most prominent predator, accounting for 60% of the total livestock losses, followed by the snow leopard (38%) and lynx (2%). Goats were the most frequent victims (32%), followed by sheep (30%), yak (15%), and horses (13%). Wolves killed horses significantly more and goats less than would be expected from their relative abundance.^[69]

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.

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.^[70]

Trapping and breeding for fur

Wolves are frequently trapped, in the areas where it is legal, using snares or leg hold traps. Wolf trapping has come under heavy fire from animal rights groups, who allege that unskilled trappers can create unnecessary suffering for the animal involved.^[71] Proponents counter that trapping, using the right tools and equipment, can be considered as humane as traditional hunting.^[72]

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. Wolves' varied coats make it difficult to create fur coats.

It is known that some Native American tribes would occasionally raise wolf pups for their fur. The pelt served as a shield against the cold and as an important addition to rituals.^[13]

Biologists may also trap wolves for research purposes. Darting and foot hold 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.

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