The photo above, from The Way Of The Wolf by David Mech, is of a lone wolf killed by wolves after entering their territory. Mech explains, "It is not unusual for wolves to die by attack from other wolves, and in some areas such 'intraspecific strife' comprises the majority of natural wolf mortality. Most such killings result from territorial disputes, involve adult wolves, and occur a few months before and after breeding season, suggesting some involvement of breeding rights as well as territorial competition."

Photo Source: The Arctic Wolf: Ten Years With The Pack​ by David Mech

Above two photos of Tundra Wolves by Tim Irvin

Photo by Alexey Tishchenko

Wolves hold greeting ceremonies after sleeping or being separated for awhile. Candace Savage, in Wolves: An Intimate Portrait, describes these as "noisy, wagful, face-licking get-togethers in which the animals rediscover one another." She explains these celebrations of family solidarity also occur when the animals first scent prey before a hunt or after a kill. The focus of festivities is frequently the alpha male. "Through this affectionate ritual," Savage says, "the animals define their group...and reaffirm their attachment to their father and to one another."

Usually the alpha male isn't particularly aggressive towards his pack. Most top-ranking males are exceptionally tolerant. Their role is to provide an emotional center for pack members to help maintain the even temper and cohesiveness of the pack. The photo at right, from Candace Savage's Wolves: An Intimate Portrait, shows wolves in a mutual display of affection and attachment. The center animal places its nose underneath its companion's muzzle in a friendly, subordinate gesture.

Wolf packs are extremely social, bonded and hierarchical. Hierarchy however, has no set pattern, rule or formula. A large, well-established pack might consist of three levels or "classes." The "upper class" is the sole breeding pair, the alpha male and alpha female. Non-breeding adults would make up a "middle class." An "underclass" might be comprised of near-outcasts, some immature animals less than two years old, and also a group of puppies. A pack might consist of only two members, a breeding alpha pair or otherwise.

There are leaders of a pack of both sexes, with each sex represented by one "top dog." Basic pack structure closely resembles a human family, according to biologist David Mech. He says, "Two unrelated, distantly related, or possibly closely related wolves mate and produce offspring each year. Some of the offspring may stay with the pack for up to four years, possibly longer." In most cases then, members of a pack are related. Long-established packs may consist of parents, aunts, uncles and siblings. Occasionally, a "disperser" or lone wolf is accepted into the pack. The newcomer may be a distant relative but this isn't always the case.

Isle Royale wolf stillbirths 

Photo Source: / May 28, 2013

Photo Source:

Even within individual wolf packs, breeding season and the consequent vying for breeding rights results in a tremendous amount of strife. Breeding season lasts for about four weeks in late winter, with adult females coming into estrus (heat) during that time. Preparations for mating however, begin much earlier, often in the fall and are marked by a sudden increase in social tension, snarling, snapping and actual fighting. Although the males do most of the scrapping, the dominant female makes the most dangerous attacks. Her animosity is directed mainly towards the other adult females, some of whom fail to become fertile as a result of the stress. Under constant assault, these females often become temporary outcasts, forced to live on the fringes of group activity.

When the actual mating time comes it is the leading female who actually initiates courtship, making gestures of sexual interest in the presence of high ranking males and by squirting urine on bushes, trees, rocks and other spots. The high ranking males start crowding around her, and soon all the males in the pack, even the pups, are usually following in her wake. They won't however, all have a chance to breed. In the photo at right, from Wolves by Daniel Wood, an alpha female in estrus (note the blood near the base of her tail) attempts to attack one of her rivals who's running with her tail between her legs.

​In large part, choice of breeding partner is made by the alpha female but the top ranking male does his best to assure no other males in the pack get a chance to breed. As the alpha female suppresses her female rivals, the alpha male is doing the same with his male competitors. It's not surprising that in an extremely high percentage of cases only the alpha male and female breed and produce pups within the pack.

Like domestic dogs, mating results in a copulatory tie. The pair remain physically attached for as long as half an hour. The photo below, from Wolves: An Intimate Portrait by Candace Savage, shows a tied alpha pair. Although the male mounts the female, he spins around once copulation is completed. The two rest fairly quietly until the tie is broken and separation ensues. 

Photo Source: The Outdoorsman, June-November 2015

As the alpha female's estrus ends, the agitated atmosphere of breeding season gradually fades. Formerly suppressed subordinate females are welcomed back into the good graces of the pack. Some may even help the alpha female prepare her den. Since some dens are occupied for decades, this may simply mean cleaning out the burrow. Wolves also enlarge and renovate old fox burrows and remodel abandoned beaver lodges. Some alpha females decide to excavate a new hole and usually choose a sandy hillside near a spring, river or lake. A female may prepare several dens, beginning work about six weeks after she conceives and three weeks before the pups are born. Gestation is about 63 days.

Wolf pups start weaning as early as three weeks of age when their milk teeth break through their gums. They eat more and more solid food as they develop, either meat regurgitated for them or carried back to them from the hunt. They follow adults as far as a mile or so from the den by the time they're five to six weeks old. They're usually completely weaned by nine weeks of age.

Subordinate pack members are very involved in the raising and care of the pups. This intrigues biologists because, according to evolutionary theory, the sole objective of an organism's life is to ensure its own personal genetic material is well represented in future stock of its species. In the struggle for survival, this is what counts - the survival of your genes into succeeding generations where they continue to influence the course of evolution. So why would a wolf who'd been forcibly prevented from producing its own offspring assist with rearing its oppressor's pups?

Wolf packs are families. Most of the non-breeding wolves who help at the den are sons and daughters of the breeding pair. Others are more distant relatives to the pups but still share their genes to some extent. This seemingly altruistic behavior fits with evolutionary theory. From a genetic point of view, a wolf that helps care for its younger siblings (with which they have the same degree of relationship as with their own offspring), or for its relatives (with which they also share genes), is really helping to ensure the survival of as high a proportion of its genes as possible into future generations. In rare cases of communal denning, where a subordinate female gives birth and brings her pups to the alpha's den for rearing, both females have a genetic stake in the other's pups. The photo below is of a year-old yearling Arctic wolf with his three younger siblings by the den.

Pack Membership and Hierarchy


Two wolf packs meet in Yellowstone National Park

Photo Source: BBC

High ranking wolf with erect posture

Photo Source:

Alpha males and females take the lead in maintaining the pack's hunting territory, their home. Territory size depends on the size of the pack and the density of prey. On northeastern Vancouver Island, British Columbia, where Black-tailed deer are abundant, a pack of ten wolves was found to occupy only about 25 square miles. In Michigan, where food is less plentiful, a group of only four wolves ranged over a total of 250 square miles. In Alberta, a pack of eight wolves was found to range over more than 500 square miles. Territorial boundaries are dynamic, as animals expand and contact their range in response to changes in their food supply. Whatever the size, a wolf pack's home ground is more or less their exclusive domain.

Tundra Wolves are the exception to this rule. They don't hold territories because they can't afford to stay in one area. Their primary prey, the Barren Ground Caribou, undergoes a dramatic annual cycle of migrations. Consequently,, except for spring and early summer when they're denning, Tundra Wolves also migrate. They trail the herds up and down the northern third of the continent. Some evidence suggests that Tundra Wolves, probably due to their differing lifestyle, operate on a different social system. A high percentage of northern females become pregnant each year. In other wolf subspecies, which are all territorial, generally only the alpha females breed.

Territorial wolf packs urine-mark their territories with scent posts, using conspicuous objects like tree stumps, logs, rocks and ice chunks. The posts appear along trails, at crossroads, and especially near the territory's edges. Most of the marking is done by the dominant male and female. Sometimes however, a whole line of wolves wait patiently for a turn to leave their mark. This joint urination festival is another way of demonstrating group solidarity. The photo at right, from The Way Of The Wolf by David Mech, shows an alpha wolf marking its territory with urine. Both alpha males and alpha females raised-leg urinate, males more often than females.

Occasionally, resident wolf packs are tolerant of outsider wolves, allowing them to cross or even sometimes to hunt on their land. R. D. Lawrence, in Trail Of The Wolf​, recounts three separate occasions in different regions of Canada where he observed wolf packs entering the territories of their neighbors. In each case, Lawrence observed the two alpha males, watched expectantly by their companions, approach each other with tails erect and hackles raised. They walked stiff-legged and slowly towards each other and when almost nose to nose, began to wag their tails. Seconds later, having taken their cue from the alphas, both packs mingled and began to play. They jumped over each other, knocked each other to the ground and even raced around in circles.

Lawrence notes however, other cases of trespassing packs where the outcome was the total opposite. The alpha males attacked each other and a battle ensued. Wolves may be badly injured or even killed. Lawrence theorizes that genetic relationships between wolf packs may explain why some packs meet in friendship at times, perhaps when food is plentiful, and at other times, perhaps when food is scarce, the same packs meet in battle. He details wolves' ability to recognize genetic relationships. He says, "Apart from having an incredibly acute sense of smell, genetic imprinting allows them to recognize the odor of their species and, it is evident, even the odor of closely related kin."

Lone wolves crossing into other's territories encounter even more danger in doing so, mainly because if a fight ensues they have no backup. Lone wolves are often subordinate animals who've dispersed from their original pack due to physical and mental harassment, intimidation, hunger from inadequate food supplies, or because of a need to mate. Loners may also be deposed alpha animals who either chose to stay alone or are looking for another pack to join. Since lone wolves are either chased off, killed, or accepted by packs they encounter, they typically make up less than fifteen percent of an established wolf population. Loners have a high mortality rate because they're often unable to catch sufficient prey and because they lack the protective support of a pack. In one study of eighteen dispersing wolves on Isle Royale, Michigan, at least ten,, 56 percent, died within the one-year period they were studied.

The alpha female gives birth in isolation, inside her cozy den smelling of spring and damp earth. As each pup emerges she licks it roughly to remove the amniotic sac. She then chews through the umbilical cord, severing the puppy from her, and finally licks the baby again until it's clean and dry and snuggled against her side. Generally, it takes about three hours for an alpha female to whelp a typical litter of five or six pups.

​At birth, the puppies do little but squirm and suckle, aware only of the warmth of their mother and of her milk. Their eyes begin to open by about seven to ten days of age. Although their eyes begin to focus soon after they're opened, it takes the pups a few days to attain clear vision. By three weeks of age they're walking, hearing, growling and chewing. At about this age, they begin poking their round heads out of the safety and comfort of their den. Naturally bolder as they age, they're prevented from straying too far by their mother or babysitter in charge. The photo below, taken from David Mech's The Arctic Wolf: Ten Years With The Pack, shows a wandering Arctic pup being taken back to the safety of its den.

Pack dynamics are always open to change. Although they usually remain more or less uniform for a number of years, inevitably, illness, death, dispersement and aging force changes in the pack's hierarchical structure. For example, an aging alpha female may be deposed of her top rank by her daughter who then takes over the role of mate to her father. Inbreeding occurs regularly within wolf packs and is an evolutionary tool. It ensures that the best of the best - those with top genes - survive.

In his decade-long study of an Arctic Wolf pack, Mech observed a number of changes in top rank. Notably, Left Shoulder took over Alpha Male's role to breed with Mom. In subsequent years, Whitey replaced Mom as mate to Left Shoulder. Since Alpha Male, Mom and Left Shoulder were already present in the pack in 1986 when Mech arrived, he didn't know their relationship, if any, to each other. But he documented that Whitey was the daughter of Mom and Alpha Male, one of three offspring resulting from their 1987 breeding. The photo at right shows Whitey, who took over the breeding role from her mother in 1990, with two of her pups.

Robert H. Busch discusses inbreeding in The Wolf Almanac, noting that it's been observed in both wild and captive wolf populations. Although there was no evidence for years that inbreeding was harmful, it's now known that under specific circumstances wolf populations can suffer from "inbreeding depression," the negative physical effects of inbreeding.

A 1991 study of wolves in Scandinavian zoos suggested that inbreeding had caused loss of genetic variability resulting in blindness, weight loss in juveniles, reduced reproductive ability and reduced longevity.

Other studies, concerning the isolated wolf populations on Michigan's Isle Royale, found that after numerous years and generations of offspring, wolf numbers plummeted to all but zero. Suffering from reproductive failures and population decline due to inbreeding depression, Isle Royale wolves now number only three, two adults and one nine-month-old pup as of 2015.  A far cry from 50 wolves, the highest number attained and recorded in 1980, the wolf population was about half that, 24 wolves, by 2009. Just four years later in 2013, the wolves numbered only nine.

All Isle Royale wolves originate from a single pair that migrated to the island in 1949. In fact, all Isle Royale wolves' DNA can be traced back to one ancestor. The photo at right is one of the last remaining three wolves, the nine-month-old pup. Its apparent hunched back and disfigured tail is the result of inbreeding depression. Spinal deformities caused by inbreeding (photo below) make walking and running painful for Isle Royale wolves. The deformity pictured below pinches nerves and impairs tail and hinquarter movements.

In most wild situations inbreeding is alternated with the input of new genetic material. Consequently, this balance works out for the best. The best possible genes are surviving, contributing to the long-term survival of the pack and therefore, the long-term survival of the species.

Lone wolf in Yellowstone who became a legendary alpha female

Photo ​Source: NatGeoWild

Hierarchical Posturing

Photo Source: Oyvind Nordahl Naess, NTB scanpix


Breeding Battles

Photo Credit: Humans For Wolves

Territory is Everything

Puppies: The Center of a Pack's World

Wolves are extremely social. There are constant interactions among pack members. Pack leaders stand tall, hold their ears and tails erect, and look other wolves directly in the eyes. Dominance/submission routines are common and occur throughout the day, reaffirming each wolf's status within the family. Subordinate wolves repeatedly show either active or passive submission. A subordinate wolf displaying active submission slinks towards the leader on bent legs, tail low and ears slicked back. It bunts its nose against the superior's face in greeting. Passive submission is displayed by sprawling on their backs with their feet in the air.

​The photos at right and below from R. D. Lawrence's Trail Of The Wolf, illustrate active and passive submission. The top photo at right shows active submission with the wolf in the background flattening its ears and holding its head and tail down in response to the higher ranking member in the foreground. Below, the low ranking wolf displays passive submission by lying on its back with legs up to indicate acquiescence to the alpha male and female.

Lone wolf in Lamar Valley at Yellowstone National Park

Within the first couple of months, the entire pack usually relocates to a new den site. Pups are normally transported, one by one, in the jaws of their mother. When the pups are about eight to ten weeks old, too big and energetic for a burrow, the pack relocates to an open-air "rendezvous" site. The pups restrict their play within this area and all the adults return to it each day. A succession of similar meeting places is used until about September, when the yearly cycle of breeding and birth begins once more.

​Like domestic dog pups, wolf puppies are playful and innocent. But all their games have a much more serious side. Through these, they first begin practicing their hunting skills, learning the subtleties of wolf body language and begin exploring the variety of wolf social relationships. Reminiscent of puppyhood, adult wolves never lose their puppy side and never become too old to play.

Pups are the center of a wolf pack' world and their arrival is the happiest time of year for the pack. The den is a hub for pack activities throughout the summer. When the adults go off to hunt - all together, alone or in small groups - the mother or babysitter stays with the pups at the den. When the hunters return, they're met by an eager mob of pups who bite, lick and nudge insistently at the adults' mouths. This begging for food stimulates the adults' regurgitation of a heap of half-digested meat.