How Do Wolf Packs Work? The Family Behind the Myth of the Alpha

In 1947 the Swiss biologist Rudolf Schenkel published observations of wolves kept together in Basel zoo, unrelated adults confined in a small enclosure, and found them fighting for rank. The American biologist David Mech drew on that work in his 1970 book The Wolf, which became the standard reference, and the terms alpha and beta went from there into dog training, business books and folklore. Mech then spent thirteen summers on Ellesmere Island in the Canadian Arctic, where wolves unafraid of humans let him watch them at close range, and saw no fighting for rank at all, because the pack was a breeding pair and its offspring. He published a paper in 1999 explaining the error and has asked his publisher to stop printing the book; the captive wolves had behaved like inmates, not like a family, and the science had described the prison.

A pack begins when a young male and a young female, each of whom has left their own family, meet, pair and claim a territory. They breed once a year, in late winter, and the female gives birth to four to six pups in a den in spring. The pups stay with their parents for one to three years, hunting with them and helping to raise the next litters, before dispersing to find mates of their own, so a pack in any given year is typically the parents, this year's pups, and one or two older offspring, six to ten animals. Larger packs are extended families with several litters still at home; the biggest reliably recorded, in Yellowstone, reached thirty-seven. The parents lead because they are the parents. They decide when to travel and hunt, eat first at a kill and feed the pups by regurgitation, and the young defer to them the way young of most species defer to adults, without a contest.

Wolves hunt large prey, deer, elk, moose, bison and caribou, that can weigh ten times what they do and can kill them with a kick, so the hunt is a matter of testing rather than charging. A pack approaches a herd, runs it, and watches for the animal that lags, limps or is old, then pursues that one, and most chases are abandoned; in Yellowstone fewer than one in five hunts of elk succeed. When they attack it is from the rear and flanks, in a series of bites that wear the animal down, and the parents take the most dangerous positions. Some things a wolf pack does that are less well known:

• •It travels forty to seventy kilometres in a day, at a trot, along regular routes through a territory of hundreds of square kilometres
• •It marks the edges of that territory with urine and howls to advertise it, and most wolf deaths in the wild are caused by neighbouring packs defending theirs
• •It eats everything: a wolf can take in ten kilograms of meat at a sitting and then go a week without
• •It teaches: pups learn what to hunt and how by watching adults, and packs in different regions have different traditions of prey
• •It grieves: the loss of a parent disrupts a pack for months, and packs that lose both breeders usually break up

The alpha idea outlived its retraction because it was useful to people. It underwrote a school of dog training that treated a pet's misbehaviour as a bid for dominance to be met with force, which has since been rejected by most trainers and by the evidence, since domestic dogs are neither wolves nor a pack, and it gave a vocabulary to men who wished to describe themselves. The wolves, meanwhile, were being restored to Yellowstone in 1995 after seventy years of absence, and the study of them there, with every animal collared and known by number, has produced the fullest picture of wild wolf society ever assembled: the same picture Mech saw on Ellesmere, of parents and children, some of whom leave and some of whom stay, in a landscape that changed when they came back.

The return of wolves to Yellowstone produced one of the most famous stories in ecology. With wolves hunting them again, elk numbers fell, and researchers reported that the elk that remained spent less time browsing in exposed river valleys. Willows and aspens along some streams, which had been eaten down for decades, began to grow back, and beavers, which depend on willow, became more common. A chain of effects running from a predator down through its prey to plants and other animals is called a trophic cascade, and Yellowstone became its best-known example.

How strong the cascade really was is still argued. Other things changed at the same time: cougar and bear numbers rose, people continued to hunt elk outside the park, and a run of dry years affected plant growth. Some studies found that willows recovered only in patches, and that where decades of browsing had removed beavers and lowered water tables, streams could not simply return to their old state. Most ecologists accept that wolves had some effect on the landscape, but the tidy version told in popular videos is simpler than the evidence.

Dispersal does a quiet but vital job: it stops wolves breeding with close relatives. The clearest evidence comes from Isle Royale, an island in Lake Superior that wolves reached across the winter ice in the late 1940s. With moose as their main prey and no regular way on or off the island, they became the subject of the longest continuous study of a predator and its prey anywhere, running since 1958. Because new wolves almost never arrived, every breeding pair was formed from relatives, and over the decades the island's population became more and more inbred.

The results showed up in the bones. Many of the wolves developed malformed spines, and breeding faltered. In 1997 a single male crossed the ice from the mainland and bred so successfully that his descendants soon made up much of the population, a genetic rescue that in time deepened the inbreeding again, because so many wolves now shared him as an ancestor. As winters with an ice bridge grew rarer, numbers dwindled until only two closely related wolves remained by 2016, and the park service began releasing wolves from the mainland in 2018 to rebuild the population.

Wolves were wiped out from much of western Europe by the nineteenth and early twentieth centuries, but legal protection has allowed them to spread back. In Germany the first wolf family to breed in modern times was recorded in Saxony in 2000, after wolves crossed from Poland. Since then numbers have grown to well over a hundred packs across the country.

Wolves have also returned to France, the Alps, the Netherlands and Belgium, often surprising people by settling close to farmland and even towns. Their return has brought old conflicts back, especially over attacks on sheep, and governments have experimented with compensation, protective fencing and guard dogs. Each pack is still, as in Yellowstone, essentially a family: a breeding pair and their offspring from recent years.

A wild wolf pack is a breeding pair and their offspring of the last few years, led by the parents as parents rather than by an alpha who fought for rank; the dominance hierarchy of popular belief was observed in unrelated wolves confined in a zoo and spread by a 1970 book whose author has spent decades correcting it. Packs hunt by testing large prey for weakness, hold territories they defend against neighbours, and pass hunting traditions from parents to pups.