Our Wildest Wildlife


Copyright © 2010 by Bill Yenne

The Gray Wolf

The wolf goes by many common names, such as timber wolf, lobo, prairie wolf, and so on, but at present there are considered to be only two species of wolf throughout the world: the gray wolf, Canis lupus, which once ranged through most of North America, Europe and Asia, and the red wolf, Canis rufus, which once lived in the southeastern United States, but which is now on the edge of extinction. The gray wolf is sometimes divided into many different subspecies. 

Scientists believe that Eurasian and American gray wolves always remained in contact, and hence part of the same gene pool. For this reason, it is generally accepted that the subspecies have not evolved separately for long enough to become distinct species.

One of the most curious of the Canis lupus subspecies is the Japanese wolf (Canis lupus hodophilax), a miniature of the gray wolf family, and the smallest wolf in the world. Although the Japanese wolf is a tiny dog-like creature, human apprehension and misunderstanding of it led to its being both feared and revered. Because of this, throughout history it was bestowed many common names, such as okami (great god), magami (true god) and yama no kami (mountain god) . The Japanese wolf was indigenous to the islands of Honshu, Shikoku and Kyushu, where it roamed the remote mountainous areas. Its small, well proportioned frame was perfectly adapted to living in the rugged, heavily forested mountain terrain.

The US Fish & Wildlife Service recognizes four subspecies of gray wolf in the contiguous United States. These are the northern Rocky Mountain gray wolf (Canis lupus irremotus); the eastern timber wolf (Canis lupus lycaon) in the northern Great Lakes region; the Texas gray wolf (Canis lupus monstrabilis) of Texas and Mexico; and the Mexican wolf (Canis lupus baileyi). The Mexican wolf occurred in the southern part of the North American continent, overlapping the range of the red wolf (Canis rufus). Both of the latter animals, the Mexican wolf and the red wolf, have come perilously close to extinction. They are discussed separately, below.

Second only to humans in its adaptation to climate extremes, the gray wolf was once equally at home in the deserts of the Middle East, the deciduous forests of Virginia, and the frozen Arctic of Siberia. The wolf was once common to most of the Northern Hemisphere, with a range that included most of the United States, Europe and the Middle East.

Gray wolves and people evolved in the Ice Age in Eurasia and spread throughout a large part of the world in each other’s company, crossing to North America at the end of the Ice Age via the Bering Land Bridge. Though they were often in conflict, the relationship between wolves and humans was governed by mutual tolerance and respect.

Most American Indians and Inuit people (Eskimos), who retained the hunting lifestyle far longer than most cultures, revered the gray wolf, trying to emulate its cunning and hunting abilities. Like many Indians, the Ojibwa people of the Great Lakes region consider themselves spiritually more closely connected to the wolf than to any other creature. According to their creation story, in “the beginning” the wolf and the man were brothers. The original man and his brother Maengun, the wolf, traveled together to name and visit all the plants, animals, and places on earth. Later, they were instructed by the Creator to walk their separate paths and that they both would be feared, respected and misunderstood by the people that would join them on earth.

Many American Indian clans were identified with animals, such as the bear, eagle or wolf. Among various tribes across the continent, the wolf was almost always a totem animal. This meant members of the wolf clan derived strength and gained protection from the wolf, but that they could not kill it. Many of the creation myths of the North American Indian tribes focused on the paradox that man has always seen in the wolf: we feel a natural kinship with the wolf as a social animal which looks after its own in the pack, and a natural fear (or is it admiration?) of the wolf as a large and dangerous predator.

Attitudes towards the wolf changed as humans ceased to be hunter-gatherers and adopted agricultural lifestyles and domesticated the wolf’s cousin, the dog. In Europe a much darker imagery grew up around wolves. They were consistently the villains in werewolf myths and fairy tales, and Europeans saw nothing admirable in wolves. Of course Europe was much more closely settled than North America, so that wolves and men were bound to come into conflict before firearms were common.

During the great wars of Europe, when hundreds of dead were left on the battlefields, the wolves would come to feed on the carcasses. Such wolves developed a taste for human flesh and there are accounts of wolves entering into towns and attacking people during the Middle Ages. In 1439 wolves are reported to have eaten four women in Paris. So some of the wolf horror stories were based on fact, but the fictions also proliferated, and when Europeans settled in North America they brought their fear and hatred of the wolf with them.

The last wolves were exterminated in the British Isles in the eighteenth century. By the twentieth century, wolves had disappeared from most of Western Europe and Japan. Remnants of wolf populations still exist in Poland, Scandinavia, Russia, Portugal, Spain, and Italy. While the gray wolf formerly ranged over the greater part of the North American continent, it was most abundant in the Great Plains. When the bison herds in countless thousands were seeking new pastures, the gray wolf flourished, preying on the newly born calves, as well as feeble, wounded, or aged bison. Today they are found only in the far north of the United States and the remotest corners of Europe, though they are present in Alaska, as well as almost all of Canada except the Maritime provinces.

Within North America, the habitat of the wolf is also incredibly varied, probably depending more on prey than on the cover or comfort provided by vegetation or landform. Wolves choose home territories in forests and meadows, in mountains with rocky ridges, lakes or rivers, in the great plains or on the tundra of the far north. In the West, wolves have been known to follow the seasonal movements of elk or bison herds, but in central Alaska, wolves don’t follow migrating moose or caribou outside their pack territories.

A pack uses a distinct territory, which it defends against other packs, but during the winter, wolves may travel long distances, especially when the main prey is a migratory animal, such as the caribou. Wolves need a large, remote area relatively free from human disturbance where they live in packs of two to 20, depending on the physical size of available prey. Where deer are the main prey, packs number from five to 10 wolves, but when the prey is large, like moose or caribou, packs are larger, and also territories. Each pack has a territory that is marked and defended.

Sizes of individual wolf pack territories reported from the Great Lakes area ranged from 30 to 260 square miles, but average approximately 100 square miles in Wisconsin and Minnesota. However, one pack of five animals monitored in the Upper Peninsula in 1992-1993 used an area of 310 square miles. In the Arctic, where the prey is musk ox and snowshoe hares, a pack may cover several thousand square miles, and on Ellesmere Island one pack covered 5,000 square miles in only six weeks! Territory size fluctuates each season, depending on the size of the pack and the number of prey.

Wolves are large in comparison to coyotes, with body dimensions exceeding those of a fully grown German shepherd or Alaskan malamute. Male wolves are slightly larger than females. Weights of adult gray wolves range from 60-115 pounds and average about 75 pounds, but there is a lot of variation— a large wolf was recording in Alaska as weighing in at 175 pounds. Gray wolves are about six feet long from nose to the end of the tail. Adults stand 26-38 inches tall at the shoulder, but Mexican wolves and red wolves are considerably smaller.

Gray wolves vary widely in appearance. They are often pure white and more slight of build in the Arctic, while in the taiga or northern forests of Canada and the United States they are larger and dark gray or black. However, there are also pale gray wolves and cream or tan wolves with brindled backs. In cold climates the dense underfur in their winter coats is protected by guard hairs which may be up to six inches long over the shoulder. The feet of wolves are large, with tracks measuring 3-4 inches wide and 4-5 inches long — nearly as large as the palm of a human hand. Wolves have cheek tufts that make their faces appear wide and their heads large. Their tails are bushy and straight, not curled like that of most dogs.

Wolves are among the most social of carnivores. The pack is the functional unit of wolf society, and the animals within the pack depend on cooperation for survival. A pack is typically comprised of two lead or, “alpha,” animals, the current year’s pups, siblings from previous litters, and occasionally other wolves that may or may not be related to the alpha pair. The alpha male and female normally are the only animals that breed, even though other pack members are physiologically capable of reproduction.

The alpha animals are thought to lead in decisions such as when and where to hunt and when it is time to move, rest, or find seclusion. The alpha female is believed to select the denning site. Much of the time that the pack spends together is used to reinforce the intricate dominance hierarchy within the pack through structured greetings and body posturings. The alpha pair always takes the first food from a kill. Wolves which are subordinate to the alpha pair, approach them with their heads low, and their tails between their legs. Or they roll over and present their bellies or groin areas to be sniffed. Even from the air the dominance hierarchy of a pack can be viewed as the wolves often travel single file, the alpha pair carrying their tails high, while the subordinate wolves are holding their tails appropriately lower.

The hierarchy within a pack changes as some wolves age, or get sick, and younger ones gain in strength and maturity. Old dominants may become subordinates, or they may be chased out of a pack. Then they become dispersers, or lone wolves, often traveling hundreds of miles, hoping to find another pack or a new territory to find a mate and start their own pack. One such wolf moved 550 miles, from south of International Falls, Minnesota to eastern Saskatchewan. It is in this way that new packs have recently been formed in the northern United States by dispersers from Canada.

Pack life centers largely around mating, which takes place in midwinter, usually in February. In fact much of the dominance hierarchy is actually based on reproductive rights — who is allowed to mate and reproduce. Females usually become sexually mature at about 22 months. Although only the alpha pair will reproduce, subordinate males may mate with the alpha female before she becomes fertile. As her time of ovulation approaches, the alpha male becomes very protective and aggressive towards all other subordinate wolves. Subordinate females who are mature enough to bear young appear to be inhibited from becoming fertile — perhaps by stress from the increased dominance of the alpha pair.

This pair forms a strong bond and are often lifelong mates. After mating, they withdraw from the pack to den together.

Wolves often build their dens in well-drained soils in meadows near water, and they may use the same den for several years. Wolves also den under tree roots, rock outcrops, hollow logs, or even in former beaver lodges. Dens are usually dug by early March. Gestation lasts 60 to 63 days, and pups are born in late April. Litter sizes range from one to nine pups, but average four to six.

The pups are born blind and depend completely on their mother’s milk for the first month. They are weaned at about five weeks and moved to a rendezvous site (a meadow or an open area in the forest) at about eight weeks. Now the pack will reassemble as all pack members feed and care for the pups. Indeed, the whole group assists in the upbringing, acting as baby sitters when the mother herself goes hunting, and guarding the area from predators, such as grizzly bears. This activity strengthens the social bonds among pack members, which is critical for their survival as communal hunters. As the pups grow, they are fed partially digested food brought to the den or rendezvous site and regurgitated from the stomachs of returning adults. During the summer, the pack may change its rendezvous site several times.

By the end of summer, the pups are beginning to hunt with the adults, and the pack is once more able to be on the move.

Wolves are among the best examples in the animal world of population self-regulation, limiting production of pups by allowing only the alpha pair to breed. Litter sizes for wolves also vary, with larger litters being born when prey is abundant, while during lean years the pack may not breed at all. There is about 60 percent mortality for pups and young wolves.

Death is usually caused by starvation or disease, but also by battles between wolf packs or from predation by bears. Adult wolves live for eight or nine years in the wild. Adult wolves are not attacked by any predators, besides man. The main causes of death are accidents, malnutrition, starvation, parasites, diseases, and fatal encounters during territorial disputes between packs, or with humans.

Because they live in packs, wolves are able to cooperate when they hunt prey larger than themselves, such as elk, deer, and moose, or in the far north, caribou, reindeer and musk ox. Before the late nineteenth century, the bison was a key source of food for wolves living on the Great Plains of North America. Other large prey include pronghorn antelopes and bighorn sheep. When hunting larger prey, wolves seek out the weak and vulnerable, the young of the year and the old or sick. A wolf can consume up to 20 pounds of meat at one meal, and usually utilizes the entire carcass, including some hair and bones. Wolves will also prey on game birds, waterfowl, rabbits and smaller mammals, such as beaver and various rodents. In Yellowstone National Park, wolves attack bison, and they’ve been known to kill black bears. Wolves also prey on domestic livestock and poultry, and of course this predation has increased as ranches and farms have taken over the lands once used by their wild prey.

Smaller prey, such as beavers, rabbits, and other small mammals, may be a substantial part of the diet of lone wolves. Indirectly, the kills of wolves support a wide variety of other animals: ravens, foxes, wolverines, vultures, and even bears feed on the remains of animals killed by wolves. Wolf kills have also been found to be an important source of food for eagles.

When large prey, such as caribou or moose, are abundant, wolves live in larger groups to enable pack hunting. This enables them to take larger prey, and has given rise to the frightening picture of a pack of ravenous wolves terrorizing their prey and decimating their numbers. The relationship between wolves as predators and their prey was intensively studied by David Mech on Isle Royale. Isle Royal National Park was established in 1931 on an isolated island in Lake Superior primarily for the protection of the native plants and animals, including woodland caribou, lynx and coyotes. Moose had swum to the island in about 1912 and their population numbers had exploded. Then in 1948 a single pair of wolves crossed an ice bridge to the island, creating a great opportunity to study the relationship between predators and prey in a closed system. Mech’s long-term studies at Isle Royale proved that, at least in the Isle Royale system, wolves did not actually regulate the numbers of their prey — the numbers of both predators and prey were regulated by the amount of food available, especially in winter.

However, they did act as an effective population control by taking the weakest members of the herd, the calves, and the older moose which were sick with disease. Many moose get an infestation of ticks and hydatids which cause cysts in their lungs, so that they can hardly breathe. Such animals are natural prey for the wolves, and predation by wolves is a natural way of culling out the unhealthy animals in the moose population. However, even in their attacks on the weaker animals of a herd, the cooperative hunting techniques of a pack are the most effective way to bring down such large prey as a moose, which may weigh in at 1,000 pounds, easily 10 times the weight of one wolf. Even a pack of wolves has a hard time bringing down such large prey — they are not able to simply take a larger animal such as a moose or a deer any time they feel hungry. In fact, Mech’s studies showed that wolves approach about twelve deer or moose for every one they actually catch.

A formal monitoring program of the moose and wolves on Isle Royale began in 1958. Wolf numbers have varied between 12 and 50; moose numbers, from 500 to 1,900. The wolf and moose populations on the island followed a pattern of dynamic fluctuations, wherein high moose numbers (particularly numbers of older moose) were followed by higher wolf numbers. Wolves influenced moose numbers predominantly through the direct killing of calves and have remained the only consistent source of moose mortality on the island. The moose-wolf population patterns held until a dramatic crash occurred in the wolf population in the early 1980s, in which wolf numbers dropped from 50 to 14 because of the accidental introduction of the disease, canine parvovirus, or canine distemper. As the moose population grew throughout the 1980s and 1990s, the wolf population increased to only about 35 by 2004. 

Humans understand their world mainly through sight and communicate with words. Wolves have good eyesight, but they read the world and communicate most extensively through their sense of smell — probably their most acute sense. The pack delineates its territory, and the individual marks his presence by placing scent marks, especially urine or scat. Scat may bear the odor of hormone secretions from the anal glands. Wolves also scratch the ground to leave both a visual and an olfactory mark of their presence. Thus, the entire territory of a pack is marked — the trails and rendezvous sites, as well as the boundaries — and a wolf traveling through it will be able to read the signs and know who passed that way recently, and perhaps even what mood it was in.

Wolves also communicate vocally, using whines and whimpers, growls, barks and howls. Whines are plaintive begging sounds, and they may indicate pain, but they are also used by pups or subordinate wolves towards a dominant adult. Growling indicates anger or aggression. Usually it is directed at another wolf and may begin a dominance fight. A bark seems to be a warning; it is often used by an adult disciplining pups. And of course, wolves howl.

Anyone who has heard the sound of a wolf howling in the northern woods by night will agree that the wolf howl is the most enigmatic and fascinating of all the noises made by wolves — or perhaps of all the noises heard in the wild. For some humans it is the voice of the wilderness. For others it is the sound of evil which strikes a chord of fear and hatred. The noise itself is very complex, a long, drawn-out, continuous sound, with one fundamental tone overlaid with two or three related harmonic tones. Wolves most commonly howl in the late evening or early morning. They never yap in combination with their howls, as coyotes do. Howling is much more common during the mating season, in midwinter, and during the raising of pups at the rendezvous sites in midsummer. There is less howling in early spring, probably in an effort to protect the den site. In spite of many studies, biologists are still not sure why wolves howl. It is thought that howling is used for gathering the pack together before a hunt and for territorial announcements to other packs — but it remains a fascinating mystery to man.

In recent years, biologists have learned to use howling to study wolves. The researcher can howl out into the night and the wolves will answer. Surely they must know that this is not another wolf, but for some reason, they enjoy the game. The researcher gets information about the whereabouts and even the numbers of packs much more easily than he would be able to by walking the woods and reading the signs of tracks. Howling has also become a tourist attraction at several parks in Canada, and at the International Wolf Center. The practice began in Canada at Algonquin Provincial Park in 1963, when park officials asked biologists who were surveying wolf populations if they would give a demonstration of howling and allow the visitors to hear the response.

The International Wolf Center is located at Ely, Minnesota, where gray wolf research has been conducted since the 1930s, going back to the pioneering work of Sigurd Olson and Milt Stenlund. In recent years, the work has continued under the direction of noted wolf biologist David Mech, who has tracked and studied wolves there since 1966, and who is regarded as the foremost international expert in the field.