• wolf laying down

This section is a great place to begin learning all about wolves. Information in this section will start with the basics of wolves around the world and carry you through more advanced publications.

IDENTIFICATION

It can be difficult to distinguish between a gray wolf, also referred to as a timber wolf, and a coyote–especially at a distance. Generally wolves are larger and bulkier with long legs while coyotes tend to be sleeker, shorter and light on their feet. Wolves measure five to six feet and weigh fifty to one hundred pounds while in contrast coyotes are 3.5-4.5 feet and weigh twenty-five to forty-five pounds. Wolves also have erect, round furry ears whereas coyotes ears tend to be pointed.

Wolf tracks are usually 3.5” or larger not including claws and generally use a direct registration when they walk, meaning the hind foot steps in line with the front foot. Wolves generally travel by walking or trotting in a fairly straight line and dogs tend to zig zag or follow a random path.

Wolves howl in long low tones and to hear a wolf howl in the wild can be a trilling experience. Wolves seldom bark. Coyote howls are generally mixed with yip, yelps, and barks and are higher pitched.

BEHAVIOR

Wolves are social animals which live in a family group or pack. The number of wolves in a pack can be highly variable, but typically packs have six to ten members. This pack consists of a dominant (alpha) male and an alpha female (a breeding pair), along with pups from the previous year and the current year’s pups. Other subordinate adults may join the pack occasionally. The breeding pair is in charge of the pack, raising the young, selecting denning and rendezvous locations, and maintaining the territory.

A wolf packs territory can range from twenty to one hundred twenty square miles. The size of the territory is determined prey densities. In low prey density areas, such as northwestern Canada, territories can reach hundreds of square miles. Wolf territories may share a common border, but seldom overlap by more than a mile. A wolf that trespasses in another packs territory runs the risks of being killed by that pack. Territories are clearly marked by scent messages—urine and feces—left by the pack. Howling helps define territories, as well as identify and reunite wolves scattered over their territory.  Historically, wolves once occupied every habitat that had sufficient prey in North America from mid Mexico to the polar ice pack.

Wolves that leave their natal pack to find new territory are referred to as dispersers. Dispersal is the primary way wolves colonize new areas and maintain genetic diversity. Dispersers may travel hundreds of miles to find and establish a new territory. Wolves have been known to disperse up to 550 miles, but more commonly disperse fifty to one hundred miles from their natal pack.

Generally wolves disperse when one to two years old as they reach sexual maturity although some adults disperse also. Dispersers usually leave the pack in autumn or winter. At any one time five to twenty percent of the wolf population may be dispersing individuals. Usually a wolf disperses to find an individual of the opposite sex, find a territory, and start a new pack. Some dispersers join packs that are already formed. It is not clear as to why some wolves disperse and others don’t. Some wolves stay in their natal pack and work their way up through the dominance hierarchy.

BREEDING & DENNING

Wolves are sexually mature at two years old, but seldom breed until they are older. In each pack, the dominant male and female are usually the only ones to breed. They prevent subordinate adults from mating by physically harassing them. Thus, a pack generally produces only one litter each year, averaging five to six pups. However, in areas where there is a high ratio of prey per wolf, there can be multiple litters per pack.

Packs create a den for the alpha female to birth her pups in. The den’s entrance tunnel is six to twelve feet long and fifteen to twenty-five inches in diameter.  Sometimes the female selects a hollow log, cave or abandoned beaver lodge instead of making a den. After a gestation period of sixty-three days, four to six pups are born in late-April or early-May. This annual event is timed so the pups are not subjected to the extreme cold of winter immediately upon birth, and other Northern hemisphere mammals are birthing at the same time. This pattern has evolved so the pack has ample prey in the form of elk or deer fawns.

At birth, wolf pups are deaf and blind, have dark fuzzy fur and weigh about 1 pound. They grow rapidly during the first three months, gaining about 3 pounds each week. Pups begin to see at two weeks old and can hear after three weeks. At this time, they become very active and playful. The mother resides in the den for the first several weeks after birth while the pack hunts.  Occasionally the alpha female will appoint a ‘pupsitter’ to watch over the puppies when she must leave.

When pups reach about six weeks old, they are weaned and the adults begin to bring them meat. Adults eat the meat at a kill site often miles away from the pups, then return and regurgitate the food for the pups to eat. The hungry pups jump and nip at the adults’ muzzles which stimulate regurgitation.

The pack abandons the den when the pups are six to eight weeks old. The female carries the pups in her mouth to the first of a series of rendezvous sites or nursery areas. These sites are the focus of the pack’s social activities for the summer months and are usually near water. Wolves will never use a den again during their lives, unless they are the breeding female. Dens are only used for birthing pups and not as sleeping areas or to escape the elements.

By August, the pups can wander up to two to three miles from the rendezvous sites and use the sites less often. The pack abandons the sites in September or October and the pups, now almost full-grown, follow the adults.

Pup survival is directly related to prey availability. Prey availability is generally higher in areas that are being newly colonized by a breeding pair.  The overall survival rate of yearlings and adult wolves has been documented in the western Great Lakes region between sixty percent and eighty percent. Grey wolves can live up to thirteen years in the wild.

HABITAT & FOOD REQUIREMENTS

Wolves require large areas of contiguous habitat that can vary greatly, including forests and mountainous terrain, or in the case of the Mexican gray wolves which can thrive in desert and brush in the southwest. Suitable habitat must have sufficient access to prey, protection from excessive persecution, and areas for denning and taking shelter.

Wolves spend about eight to ten hours every day moving through their home range. It is rare that they will stay in one place for long of a periods of time.

Wolves can survive on 2.5 pounds of food per day, but require about five pounds per day to reproduce successfully. Wolves are estimated to eat ten pounds of food per day on average. Wolves may not have the opportunity to eat every day and they generally live a feast or famine lifestyle. They may go several days without a meal and then gorge on over twenty pounds of meat when a kill is made. Wolves primarily feed on prey animals larger than themselves, as this provides food for many individuals. However, wolves will prey upon smaller mammals such as beaver and hare. Because wolves as a species, inhabit a much wider area than its prey species, different populations of wolves prey upon different animals. Wolves located in the Western Great Lakes region typically prey upon whitetail deer whereas wolves in central Canada prey primarily on caribou.

As these prey are so well adapted to protecting themselves, wolves feed upon the vulnerable individuals, such as weak, sick, old, or young animals, or healthy animals hindered by deep snow. By killing the inferior animals, wolves can help increase the health of their prey population. When inferior animals are removed, the prey population is kept at a lower level and there is more food for the healthy animals to eat. Such “culling” also ensures that the animals which reproduce most often are healthy and well suited for their environment. Over many generations, this selection helps the prey become better adapted for survival.

Wolf predation on ungulates (hooved animals) varies seasonally. Predation is highest during mid to late winter, when animals are suffering from poor nutrition and the snow is deep, giving an easier hunt. It is also quite high in early summer when prey animals have their young, as wolves prey heavily on vulnerable young.

Reciprocally, prey availability may limit wolf numbers. In a mild winter, deer will be healthier and wolves may not be able to hunt enough animals to feed themselves.  This may cause a decrease in wolf populations. Also, several severe winters many decrease prey populations and therefore decrease the number of wolves. Another factor that complicates the effect of wolf predation, is the number of competing predators such as bears, coyotes, or bobcats. Therefore, we cannot generalize the effect that wolves have on prey populations, because it is dependent on several factors.

PLACE IN THE ECOSYSTEM

Yellowstone National Park set the stage for studying the impact of wolf reintroduction dating back to the 1990’s. Idaho’s similar landscape and climate mirror many of the same outcomes experienced by both the absence and reintroduction of wolves. Much like a ripple effect from a pebble thrown into a pond, the results of the presence of wolves are reversing seventy years of absence.

Without apex, or top predators in an ecosystem, studies indicate that ungulate populations will soar. An ungulate is a reference to deer and elk, herbivores that would ordinarily graze grasslands. Overgrazing is a common problem in ecosystems with absent apex predators. Elk are observed grazing and stripping young deciduous trees, particularly aspens and willows under seven feet tall.

Decreased aspen tree stands, especially along streams and rivers are reported leading to decreased bird and aquatic species, especially trout, frogs, and insects vital to healthy streams. As a result of poor water quality, the beaver populations decreased. Streams are reported to have “died” in the absence of these species and the obvious cause is the absence of the top predator.

Coyote populations also experience an increase. With fewer carcasses to savage upon, coyotes shift to other mammals, particularly smaller ones. That impacts other predator and prey relationships.

When healthy populations of wolves are present, ungulates are forced to move more frequently, ranging to higher elevations which is more characteristic to their history. Wolves also cull the herds of the weak, injured, and sick animals reducing the population to healthier levels. Less ungulates and more grassland seems to reduce the destruction of aspen and willow trees. The results along streams and gullies are healthier aspen and willow groves which in turns result in healthier aquatic, bird, and smaller mammal populations. With the return of the wolf, coyote populations have also decreased.

Doug Smith, biologist of the Yellowstone Wolf Recovery Program shares “Nature without wolves is not nature”. Idaho’s nature depends on the reintroduction of any species that protects a longer-term balance that impacts and regulates the natural economy of the wilderness.” –Benefits of Wolves and Healthy Ecosystems, Wolf Education and Research Center.

Sources:  

WI Department of Natural Resources
Wolf Education & Research Center
International Wolf Center

Wolves & Humans

A critical aspect to long-term conservation of wolves are the relationship of wolves to humans. Human dimensions is becoming an important part of the proper management of al wildlife.  Ultimately human tolerance of wolves will determine where wolves can live on the landscape, especially in highly modified landscapes as we have in the Great Lakes region. Learning to live with wolves means we also have to learn how people relate to wolves. To counter myths, alleviate fears, eliminate prejudices, and encourage tolerance, we need to better understand how people feel about wolves. Human dimensions research will be a critical part of any future management to maintain healthy wolf populations that benefit the ecosystems of the Western Great Lakes region.