Wolves in the wild regions of northern Minnesota typically stalk small mammals. Beavers. Deer and moose fawns. Wolves are clever and effective hunters of prey of all sizes, though, with a varied appetite when options present themselves. And at least one pack in Minnesota has learned, like thousands of fellow anglers in the upper Midwest, how to catch the trout that populate the region’s watersheds.
Scientists, or even careful observers of wildlife, have in the past seen wolves chow down on dead and dying salmon during spawning runs, when the big fish are easy to collect in shallow streams. Wolves have also been observed eating trout in Yellowstone, but it was unclear whether wolves were catching those wild freshwater fish on their own as a seasonal food source, or if they were scavenging on already-dead fish, or plucking near-dead fish from shallows, exhausted after spawning.
But biologists working with the Voyageurs Wolf Project in Voyageurs National Park tested a hunch to see if the wolves were fishing. They’d been studying the same pack for some time, learning what the animals ate and where they spent time hunting. GPS data from the animal’s collars showed them spending lots of time near a creek-fed stream that held a population of fish. Basically, the research team knew that if the pack stayed in the same place for more than 20 minutes, they were likely eating something. When they noticed the wolves they studied made a habit of spending big chunks of time lingering streamside, the biologists started wondering if the wolves were doing a bit of angling.
Finally, one day a researcher went to get a closer look at the pack’s behavior. He took shelter behind a stand of vegetation, unobserved by the pack. Suddenly, he spotted a wolf charging into the stream, then charging right out again.
“It was really crazy,” Tom Gable, the researcher, told Minnesota Public Radio. “He came within about 8 to 10 meters of me and he had no idea I was there. I was hiding in the shrubs on the edge of this creek.”
Gable noticed the wolf was eating trout parts; surely, he assumed, the commotion he’d seen had been the wolf catching the fish.
So the researchers returned when the wolves were gone, and set up cameras to capture the wolves behavior near the stream.
The footage they captured showed the wolves standing and pacing near the stream, listening to the water and watching its surface. When a fish jumped, the wolves snapped to attention and would dart into the water in pursuit. They’d spent enough time around the stream to learn splashing meant fish, and how to catch them.
“You can see the wolves abruptly head to the water several times after hearing a splash,” Gable told The New York Times. “They learned what a fish splashing in the creek sounds like, and they know that it means food. Incredible.”
Footage exists of wolves hunting for salmon alongside grizzly bears in Alaska and British Columbia, but this appears to be the first time researchers have captured video of wolves purposely stalking and catching wild freshwater fish as a regular food source.