The English-language article was published in the Royal Society Open Science journal in May. The title is: “The ethology of wolves foraging for freshwater fish in a boreal ecosystem” (New Window).
One of the article’s authors saw two wolves fishing for white suckers while observing them as part of another surveillance project in 2017. The research team was so stunned that they decided to investigate this phenomenon.
They had never seen it before and thought they would likely never see the phenomenon again, says lead author of the present study, Dani Freund. She is also a graduate student at the University of Minnesota and a member of the Voyageur Wolf Project, a wolf surveillance program.
But now we’ve had sightings of wolves fishing every spring for five years, she adds with a big smile.
By then, remains of freshwater fish had been identified in wolf droppings, but researchers weren’t sure if the wolves had been hunting fish or if they were carcasses they’d eaten.
They studied the behavior of a dozen wolves between 2017 and 2021 in the Greater Voyageurs Ecosystem, which lies on the Minnesota-Ontario border.
A gray wolf at the Assiniboine Park Zoo in Winnipeg.
Photo: Radio Canada / Gavin Boutroy
Our work provides evidence that wolf ‘trapping’ behavior is likely widespread in similar boreal ecosystems but remains difficult to study due to its short-lived nature, the paper states.
The boreal forest stretches from Alaska to Newfoundland and from the US border to Hudson Bay.
We observed wolves from different social groups fishing in four different streams and rivers. There were packs and individuals. Males, females, breeding animals and juveniles. Given this diversity, we believe that when wolves and fish are in the same place, the wolf benefits from the fish, explains Dani Freund.
Creative Monitoring
To conduct this study, researchers used radio collars to measure wolves’ proximity to waterways, wildlife cameras, field observations, and a video camera-equipped radio collar. This is the first time such a collar has been placed around the neck of a wild wolf.
This camera collar was a model called the Vectronic-Aerospace Vertex Plus. She recorded a 30-second video at the beginning of each hour of the day for 43 days.
One of these videos clearly shows a wolf fishing with its paws in the water. We see scales falling from the animal’s snout and a tattered fish on the ground.
A fish carcass at the feet of a wolf seen by a camera on a transmitter collar.
Photo: Traveler Wolf Project
I was part of the team that put the collar on him, it was quite a process. We didn’t know what it would be like. “Most of us thought that as soon as we put it on the wolf, mud would splatter on the lens and we wouldn’t see anything,” says Dani Freund.
“The fact that we caught the wolf doing anything, and especially this really cryptic behavior, is incredible,” she adds.
According to the researcher, developing a method for monitoring wolves required a lot of creativity. It is really difficult to spot wolves in the northern forest as it is dense and full of insects. It’s quite a strenuous walk to get there unless you’re on a hiking trail.
fish with his ears
According to the study, wolves hunt white suckers mainly during the spawning season, which lasts about 20 days in spring. At this time, the fish come together for reproduction. Wolves are often fished near beaver dams where the current brings the fish closer together.
wolves [attendent] B. on the bank of a stream or when wading in less than a meter of water to visually or additively recognize a fish and catch its prey by dipping its snout in the water, the article states.
When available, fish is the favorite food of the gray wolves in the northern forest.
Photo: Travelers Wolf Project
In videos captured by a wildlife camera at night, a wolf can be seen wagging its ears before catching a fish.
Our video evidence suggests that auditory cues are particularly important for this behavior [de pêche]since wolves hunt at night when visual cues are inhibited, the researchers say.
The study notes that the wolves may kill fish and create a reserve with them on the bank to make the most of the availability of this food source.
For Dani Freund, this behavior corresponds to new findings about the diet of wolves in recent years. The diet of wolves is much more flexible than hunting caribou, elk and deer, which is what we thought, the biologist points out.
We have observed that wolves eat a lot of blueberries in summer. Much of the Voyageur Wolf project’s initial research revolves around wolves hunting beavers, which was not really known until recently. It seems like wolves can take advantage of what’s in front of them when it’s in front of them, she continues.
The gray wolves at Assiniboine Park Zoo in Winnipeg are from British Columbia. You have acted in several films.
Photo: Radio Canada / Gavin Boutroy
Wolf specialist and professional teacher at the Université de Saint-Boniface, Daniel Dupont, agrees with this observation. He has participated in collar and wildlife camera studies in Manitoba.
He endorses the methodology of this study and is not at all surprised by these conclusions. He himself found fish scales in wolf droppings, presumably from fish left on the ice by fishermen.
They are animals that adapt very well to different environments and, ultimately, like any other species, wolves want to feed themselves, reducing the amount of energy they have to expend to find that food and reduce the risk when trying to capture their prey, says the Manitoba biologist.
A study highlighting the interdependence of species
The article points out that wolves fish for beavers along dams, a species that is usually prey. For Dani Freund, it shows the interconnectedness of the environment and what happens when an animal changes it.
The beaver changes the landscape it inhabits […] We have known for some time that beavers create habitats for other species. But it’s interesting to see how beavers affect this top predator of the boreal ecosystem and what opportunities they offer it, apart from being just prey, she points out.
Daniel Dupont himself observed other aspects of the interdependence between beavers and wolves. They will also use old, abandoned beaver huts as dens to give birth to the young, he notes.
The wolf specialist and lecturer at the Université de Saint-Boniface, Daniel Dupont.
Photo: Radio Canada / Gavin Boutroy
All species play a specific role in the ecosystem, and sometimes roles that we understand well. Sometimes there are roles that we don’t understand at all and the relationship between certain species is sometimes much more complex than we think, the biologist continues.
As we can see from this research here, in fish, beavers and wolves, the behavior of one influences the behavior of the other, and in a way they help each other.
The researchers say their findings underscore the need for streams and beavers to be around the wolves. This is information that could aid ongoing wolf reintroduction efforts in North America and Eurasia.