If Santa’s reindeer share the misfortune of migrating caribou in northern Quebec, there’s a good chance they’ll have a pack of wolves on their heels during their December 25 jaunt. In fact, a study published in the scientific journal Oikos shows that most wolves in Northern Quebec put aside their territorial behavior to follow the caribou on their annual migrations.
In North America, the gray wolf is generally considered a territorial species that doesn’t travel far," points out study leader Steeve Côté , professor in the Department of Biology and researcher at Université Laval’s Centre d’études nordiques. What was less well known, however, were its living habits at the northern limit of its range. We therefore decided to study the question, in part to document the role of this predator in the decline of the Rivière-aux-Feuilles migratory caribou herd. This herd’s numbers have fallen from over 628,000 individuals in 2001 to less than 200,000 today."
The caribou of the Rivière-aux-Feuilles herd spend the winter in the boreal forest. When spring arrives, they migrate north to their calving grounds on the tundra. After calving in June, the caribou head for the summering grounds, also on the tundra. From late September onwards, they head back to their wintering grounds. "In a straight line, over 700 km separate the Rivière-aux-Feuilles herd’s summering and wintering grounds. This is the longest migration made by a land mammal in North America," points out Steeve Côté.
Researchers fitted GPS collars to 59 wolves (one per pack) and 431 caribou from the Rivière-aux-Feuilles herd. Tracking the animals’ movements between 2011 and 2021 revealed a little-known face of the predator. "We discovered that only 17% of the wolves studied were sedentary, while 47% followed the caribou to the treeline, over distances ranging from 150 to 400 km, and 36% accompanied the caribou throughout the year. This means that more than 80% of wolf packs follow caribou during some or all of their migrations", summarizes the researcher.
Interestingly, in spring, wolves head north about three weeks before caribou. "They take advantage of this period to scout out dens and give birth to their pups," explains Steeve Côté. They intercept the caribou as they head for their calving grounds."
The wolf’s migratory behavior in northern environments is neither new nor fixed, believes the researcher: "There’s no reason to believe that these migrations are a recent phenomenon. If no one has mentioned them until now, it’s because no studies have been carried out on marked animals. Moreover, the same pack may be migratory one year and sedentary the next. The three tactics we describe demonstrate the great plasticity of wolf behaviour.
"It was already complicated to manage a migratory species like caribou. Now we find we have two migratory species to manage at the same time."
-- Steeve Côté The findings of this study have implications for caribou conservation and management, continues Professor Côté. "Until now, it was thought that there was an easing of predation pressure when caribou left their wintering grounds. Our observations show that this is not the case. Managing a migratory species like caribou was complicated enough. Now we find we have two migratory species to manage at the same time."
The signatories of the study published in Oikos are Candice Michelot, Martin Leclerc, Julien Hénault Richard and Steeve Côté, from Université Laval, and Joëlle Taillon and Christian Dussault, from the Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs du Québec.
