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A large, tawny gray wolf (Canis lupus) that formerly occupied diverse habitats throughout northern North America and Eurasia but now lives in fewer, more limited areas because of human encroachment. Also called timber wolf.
Canis lupus
TAXONOMY
Canis lupus Linnaeus, 1758, Sweden. Twenty-six races are recognized. The largest races live exclusively on large ungulates while the smallest are from the desert regions. Two genetically distinct stocks appear to occur in North America, with wolves in the western part of the continent perhaps representing a separate colonization from Eurasia.
OTHER COMMON NAMES
English: Timber wolf; French: Loup; German: Wolf; Spanish: Lobo.
PHYSICAL CHARACTERISTICS
The gray wolf is the largest of the canids with males weighing up to 132.3 lb (60 kg) while females are typically 10–15% smaller than males. Shoulder height is from 26.0–31.9 in (66–81 cm). In the small desert wolves, e.g. the Mexican wolf, males weigh 66 lb (30 kg) or less. Coat color is typically an agouti brown but can vary from pure white (in the Arctic) to black, and shades of rusty color. The belly and chest is white; the fur is long with a bushy tail. The skull and teeth are large, but are less specialized for eating flesh than those of the dhole and the African wild dog.
DISTRIBUTION
Wolves occur where suitable densities of prey, usually ungulates, can provide food. This includes Arctic ice flows and the Sinai desert and all habitats in between.
HABITAT
The species used to inhabit the whole of North America, south to central Mexico. It also lived throughout Eurasia including the Sinai peninsula, but excluding the southern third of India and the southern portions of Southeast Asia. It has been exterminated from most of the U.S. except for a population in northern Minnesota, and a newly expanding population in the northern Rockies. A few Mexican wolves have been reintroduced to New Mexico in the United States. Wolves were wiped out in most of western Europe by 1750. Three small populations remain in the Iberian peninsula, the Apennines in Italy and south central Norway. Wolves have also been eliminated from the eastern two-thirds of China.
BEHAVIOR
Most wolves live in small social groups of two to six individuals, sometimes with pups. Packs are thought to consist of related individuals and females typically join males that have an established territory. However, many wolves such as those living in less productive areas are only seen solitarily or in pairs and packs themselves are fluid. Groups may split in the summer while individual pairs breed and then come back together
into larger groups in the winter. The size of the pack seems to be related to the size of the prey killed. A large group can obtain a meal from a large carcass. Little is known about the social behavior of wild wolves. However, information from many captive packs reveals a rather dictatorial society in which the alpha male exerts his authority by clasping the muzzle of the subordinates in his mouth. The other wolves show elaborate active submission rubbing their mouths against his head and licking his muzzle in a gesture derived from infantile begging. Alpha males have been seen to pick up a bone, with no food left on it, and drop it among the subordinates as a gesture of their dependence on his food provisioning.
FEEDING ECOLOGY AND DIET
Ungulates from 44.1–220.5 lb (20–100 kg) form the core of the wolf's diet. However prey up to the size of a moose (1543 lb; 700 kg) and as small as a mouse are included. Members of the deer family are the most common prey from the caribou of northern latitudes to the mule deer of the SW United States. Beavers are commonly killed in North America. Italian wolves raid human trash and some predation on livestock has been reported. There are no authenticated reports of wolves killing humans in North America, and no recent reports from Europe. Poor people in Europe and northern Asia may have been attacked by wolves in the past and there are a few reports of infants being taken by wolves in India.
REPRODUCTIVE BIOLOGY
Monogamous. Packs or pairs breed annually with young born from March-July depending on latitude. Gestation is 61–63 days and young are born blind in an underground den. The mother nurses her young and licks them to stimulate defecation and urination which she consumes so as to keep the den clean. Eyes open at about 14 days and young crawl to the surface a few days later. All members of the pack feed the pups with regurgitated food, and may carry some food items back to the den. The pups spend an increasing amount of time out of the den usually playing. As the pups become more mobile, adults may become less tolerant of their sharp teeth and frequently lunge at the pups to keep them at bay, but without inflicting any serious bites. By three months, the pups are starting to follow the pack, and will leave the area of the natal den. However, they usually cannot keep up with the hunts and are left alone or with a babysitter. The young are not fully mature until about two years old.
CONSERVATION STATUS
As indicated above, the wolf has been exterminated from a considerable portion of its range. It is a very rare animal in the United States (outside Alaska) and is listed as endangered in the U.S. Endangered Species Act. Recovery efforts have included protection and habitat acquisition in Minnesota, captive breeding and reintroduction of the Mexican wolf and reintroduction in the Yellowstone ecosystem. Wolves, without help from humans, have recolonized parts of the northern Rockies in Idaho and Montana. The remnant populations in Europe are being managed. The wolf does not survive in areas of settled agriculture but in the wilder parts of its immense range, it appears to exist in low numbers despite human persecution and some trapping for its fur. The gray wolf is not listed as a threatened species globally by the IUCN.
SIGNIFICANCE TO HUMANS
Wolves have been a potent force in human culture both economically and culturally. Wolves are still hunted through much of eastern Asia where people still herd their sheep and goats for a living. In Alaska they were killed using helicopters because they were blamed for depressing the caribou herds hunted by sportsmen. For people living a long way from wolves, the species and its howl represents the essence of wildness and it is a mark of machismo to own the dangerous and semi-wild wolves and wolf hybrids.
The noun has one meaning:
Meaning #1:
brindled gray wolf of forested northern regions of North America
Synonyms: timber wolf, Canis lupus
| Gray Wolf Fossil range: Late Pleistocene - Recent |
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 Canis lupus
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| Canis lupus Linnaeus, 1758 |
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 Range map. Green, present; red, former.
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The gray wolf (Canis lupus), also known as the timber wolf or, simply, wolf, is a mammal of the order Carnivora. The gray wolf is the largest member of the genus Canis. Its shoulder height ranges from 0.6 to 0.9 meters (26–36 inches) and its weight typically varies between 32 and 62 kilograms (70–135 pounds). As evidenced by DNA sequencing and genetic drift studies, the gray wolf shares a common ancestry with the domestic dog (Canis lupus familiaris).[2]
The gray wolf was once abundant over much of North America and Eurasia. However, as a result of habitat destruction and widespread hunting, it now inhabits a very limited portion of its former range. In some regions, gray wolves are listed as endangered or threatened, although considered as a whole, wolves are regarded as a species of least concern for extinction according to the International Union for the Conservation of Nature and Natural Resources. Wolves are still hunted in many areas of the world for sport and as perceived threats to livestock. Kazakhstan is currently thought to have the largest wolf population of any nation in the world, with as many as 90,000, versus some 60,000 for Canada, which is three and a half times larger.[3]
Being apex predators, gray wolves are integral components of the ecosystems they typically occupy. The diversity of such ecosystems reflects its adaptability as a species, as the ecosystems in which wolves have been known to thrive include, but are not limited to, temperate forests, deserts, mountains, tundra, taiga, and grasslands.
Wolves feature in folklore and mythology of cultures ancient to modern across the northern hemisphere; from the Norse legend of the giant Fenrir to more sympathetic depictions in Central Asia and the suckling of Romulus and Remus in the foundation of Rome. More familiar still are the fairy tales where the wolf appears as a villain such as Little Red Riding Hood and the Three Little Pigs. Wolf legends have also given rise to the popular horror figure of the werewolf.
Wolf weight and size can vary greatly worldwide, tending to increase proportionally with latitude as predicted by Bergmann's Rule. In general, height varies from 0.6 to 0.95 meters (26–38 inches) at the shoulder and weight ranges from 32 to 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, 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 any given wolf population typically weigh about 20% less than their male counterparts.[7] Wolves can measure anywhere from 1.3 to 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 them 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] Unlike dogs and coyotes, wolves lack sweat glands on their paw pads.[13] Wolves in Israel are unique due to the middle two toes of their paws being fused, a trait originally thought to be unique to the African Wild Dog.[14]
Wolves have bulky coats consisting of two layers. The first layer is made up of tough guard hairs designed to repel water and dirt. The second is a dense, water-resistant undercoat that insulates. 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. North American wolves typically have longer, silkier fur than their Eurasian counterparts.[15]
Fur 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 as a functional form of camouflage. This may not be entirely correct, as some scientists have concluded that the blended colors have more to do with emphasizing certain gestures during interaction.[16]
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 between 8 and 16 weeks old.[17] Though extremely unusual, it is possible for an adult wolf to retain its blue-colored irises.[18]
Wolves' long, powerful muzzles help distinguish them from other canids, particularly coyotes and golden jackals, which have more narrow, pointed muzzles. Wolves differ from domestic dogs in a more varied nature. Anatomically, wolves have smaller orbital angles than dogs (>53 degrees for dogs compared with <45 degrees for wolves) and a comparatively larger brain capacity.[19] Larger paw size, yellow eyes, longer legs, and bigger teeth further distinguish adult wolves from other canids, especially 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.[20] 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 10,000 kPa (1450 lb/sq. inch) 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.
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 involving wolves that have reached sexual maturity prior to the previous breeding season. It takes two such dispersals from two separate packs for a new breeding pair to be formed, for dispersing wolves from the same maternal pack tend not to mate.[21] 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 oftentimes lasts until one of them dies.[22]
Generally, mating occurs between January and April — the higher the latitude, the later it occurs.[22] A pack usually produces a single litter unless the alpha male mates with one or more subordinate females. 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 prevent other wolves from mating with one another.[21] Under normal circumstances, a pack can only support one litter per year, so this dominance behavior is beneficial in the long run.
When the alpha female goes into estrus (which occurs once per year and lasts 5–14 days),[23] 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.[24][25] 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.[25] 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.
The gestation period lasts between 60 and 63 days. The pups, at a weight of 0.5 kg (1 lb), are born blind, deaf, and completely dependent on their mother.[22][4] There can be anywhere from 1 to 14 pups per litter, with the average litter size being about 4 to 6.[26] Pups reside in the den and stay there for no longer than two months. 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 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.[22]
After two months, the restless pups will be moved to a rendezvous site, where they can stay safely 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, 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.[22] During hunts, the pups remain ardent observers until they reach about 8 months of age, by which time they are large enough to participate actively.
Wolves typically reach sexual maturity after two or three years, at which point many of them will be compelled to leave their birth packs and seek out mates and territories of their own.[22][27] Wolves that reach maturity generally live 6 to 8 years in the wild, although in captivity they can live to twice that age.[26] 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 be killed by other predators occasionally, rival wolf packs are often their most dangerous non-human enemy. A study on wolf mortality concluded that 14–65% of wolf deaths were inflicted by other wolves.[28]
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 wolf populations in a given area. Wolves are reported to carry over 50 types of parasites, including echinococci, cysticercocci, coeruni (all of which can attach humans) and the trichinellidae family.[29]
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.[30]
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.[31]
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.[31] 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.[31] Howling becomes less indiscriminate as wolves learn to distinguish howling pack members from rival wolves.
The Middle Eastern and South-East Asiatic wolf subspecies are unusual as they are not known to howl.[16][32]
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 from 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 by the other wolves.[33] Wolves also whimper, usually when submitting to other wolves. Wolf pups whimper when they need a reassurance of security from their parents or other wolves.
Wolves, like other canines, use scent marking to lay claim to anything—from territory to fresh kills.[34] Alpha wolves scent mark the most often, with males doing 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 purpose as urine marks, and serve as a more visual warning, as well.[34] 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.[34] 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.[35]
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]
Wolves function as social predators and hunt in packs organized according to strict, rank-oriented social hierarchies.[22] It was originally believed that this comparatively high level of social organization was related to 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 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, they help keep the pack cohesive and functional.
While most alpha pairs are monogamous, there are exceptions.[36] 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.[22]
Usually, only the alpha pair is able to rear a litter of pups successfully. Other wolves in a pack may breed, but when resources are limited, time, devotion, and preference will be given to the alpha pair's litter. Therefore, non-alpha parents of other litters within a single pack may lack the means to raise their pups to maturity of their own accord. All wolves in a pack assist in raising wolf pups. Some mature individuals choosing not to disperse may stay in their original packs so as to reinforce it and help rear more pups.
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 between 2 and 20 wolves, though 8 is a more typical size.[37] 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 other members of their own pack.[16]
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 ritualized and non-injurious, 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. These types of confrontations are more common during the mating season. Though rare, deaths can and will occur, as the average alpha male wolf kills two to four wolves in his lifetime.[38]
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.[34] Omegas receive the most aggression from the rest of the pack, and may be subjected to different forms of 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 submissive individuals are better suited for constant displays of active and passive submission than they are for living alone. Any form of camaraderie is preferable to solitude and, indeed, submissive wolves tend to choose low rank over potential starvation. Despite the aggression to which they are oft subjected, omega wolves have also been observed to be among the most playful wolves in the pack, often enticing all of the members in a pack into chasing games and other forms of play. In general, omega wolves exist to help relieve pack tension, be it as punching bags or as pack jesters.
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 chase 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.[39] 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 with their front paws. This technique is also common among other canids such as foxes and coyotes.
Wolves' diets include, but are not limited to, deer, caribou, moose, yak, and other large ungulates. The American Bison is probably the heaviest animal wolves prey on — bison weighing more than a ton having been taken down by a pack. They also prey on rodents and other small animals in a limited manner, as 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 (5lb) to reproduce successfully.[26] Wolves rarely eat each day, but compensate by eating up to 10 kg (22 lb) at a time.[26]
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.[27] Healthy animals may also succumb through circumstance. However, most healthy, fit individuals will not run from wolves and will instead choose to stand their ground. This defensive technique increases the possibility of injury to the preying wolves. The wolves, not willing to risk injury, are more likely to yield when encountered with such a bold individual. Instead, they will try to target weaker prey members that are easier and safer to hunt. Wolves are generally inefficient at killing large healthy prey, with success rates as low as 20% which is due, in part, to the large size and defensive capabilities of their prey.[40]
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.
Surplus killing is defined as the killing of several prey animals too numerous to eat at one sitting. During a surplus-kill, a predator's killing instinct is continually sparked off by the stimuli of so many prey animals unable to escape, so that the predator cannot stop killing. An instance of surplus killing by wolves was witnessed in Canada's Northwest Territories by researchers coming across 34 neonatal caribou calves, scattered over three square kilometres. The wolves had eaten only a few parts from half the calves and not touched the rest. Wolves sometimes only eat a part of their surplus-killed prey, like the tail or the internal organs.
However, conditions in nature which favour surplus killing are unusual. Consequently surplus killing in the wild is rare, though fairly common in domestic situations in which the prey animal's are usually confined and unable to escape the attackers. [41]
The gray wolf is a member of the 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).
With respect to common names, spelling differences result in the alternative spelling grey wolf. As the first-named and most widespread of species termed "wolf", gray wolves are oftentimes simply referred to as wolves. It was one of the many species originally described by Carolus Linnaeus in his eighteenth-century work, Systema Naturae, and it still bears its original classification, Canis lupus.[42] The binomial name is derived from the Latin Canis, meaning "dog", and lupus, "wolf".[43]
Classifying gray wolf subspecies can be challenging. Although scientists have proposed a host of subspecies, wolf taxonomy at this level remains controversial.[44] Indeed, only a single wolf species may exist. Taxonomic modification will likely continue for years to come.
Current theories propose that the gray wolf first evolved in Eurasia during the early Pleistocene. The rate of changes observed in DNA sequence date the South-East Asiatic lineage to about 800,000 years, as opposed to the American and European lineages which stretch back only 150,000.[45] The gray wolf then migrated into North America from the Old World, probably via the Bering land bridge (that once joined Alaska and Siberia), around 400,000 years ago. The gray wolf then coexisted with the Dire Wolf (Canis Dirus), a Canid species that was larger and heavier than the gray wolf and appeared in South America over 700,000 years ago and whose origin is still speculated. The Dire Wolf ranged from southern Canada to South America until about 8,000 years ago when climate changes are thought to have caused it to become extinct. After that the gray wolf is thought to have become the prime canine predator in North America.
At one point, up to 50 gray wolf subspecies were recognized. Though no true consensus has been reached, this list can be condensed to 13–15 general extant subspecies. Modern classifications take into account the DNA, anatomy, distribution, and migration of various wolf colonies.
| Subspecies | Classification | Status | Historic Range (see map) |
|---|---|---|---|
| Arabian Wolf | Canis lupus arabs | Critically endangered, declining | Southern 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, 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 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. | |||
| 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. | |||
| Russian Wolf | Canis lupus communis | Stable, declining | Central Russia |
| A very large subspecies. Hunted legally. | |||
| Southern-East Asian Wolf | Canis lupus pallipes | Stable | Northern Israel, Saudi Arabia, Turkey, Afghanistan, Iran |
| A small subspecies. Hunted legally in some places, protected in others. | |||
| 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. | |||
Historically, gray wolf classification has been transient in nature. As a result, there still exists some disagreement as to the status of certain possible subspecies. These are listed below.
| Subspecies | Classification | Status | Historic Range |
|---|---|---|---|
| Iberian Wolf | Canis lupus signatus | Stable | North Portugal, North-Western Spain |
| May also be part of C. l. lupus. An average-sized subspecies. Distinct for its black markings and rusty red pelage. Conservation dependant. | |||
| Subspecies | Classification | Status | Historic Range |
|---|---|---|---|
| Eastern Canadian Wolf | Canis lycaon | Not evaluated | Occupies the area in and around Algonquin Provincial Park in Ontario, and also ventures into adjacent parts of Quebec, Canada. |
| Originally thought to be a variant form of canis lupus lycaon. Smaller than grey wolves. | |||
| Himalayan Wolf | Canis himalayensis | Critically Endangered | Northern India and Eastern Nepal |
| Formerly C. l. chanco. Smaller than gray wolves. | |||
| Indian Wolf | Canis indica | Endangered | Eastern Indian subcontinent |
| Formerly thought to be a variety of C. l. pallipes, now known to be unique to India. Smaller than gray wolves. Typically reddish, tawny, or buff colored. | |||
| Subspecies | Classification | Status | Historic Range |
|---|---|---|---|
| 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. | |||
Much debate has centered on the relationship between the wolf and the domestic dog, though most authorities see the wolf as the dog's direct ancestor. Because the canids have evolved recently and different canids interbreed readily, untangling the relationships has been difficult. But molec
