Wolves at the Voyageurs National Park in Minnesota have been observed hunting freshwater fish, changing what is known about the diets of the carnivores.

Researchers from the Voyageurs Wolf Project have video footage of wolves chasing and catching fishes from a nearby creek. According to the group, the video footage was captured in spring 2018 using remote cameras.

The video was posted on Facebook on Dec. 13.

Wolves Catching Fishes

Most people think that wolves are blood-thirsty carnivores that slaughter moose and deer, but recent research reveals otherwise. In a paper published this month by the Voyageurs Wolf Project, a collaboration between the University of Minnesota and Voyageurs National Park, researchers showed that wolves are adaptable, capable of finding unique food sources wherever they may be.

During the research, the group attached GPS collars to wolves from over seven packs. They collected location data to determine pack territory and predation behaviors in and south of the national park.

Wolves still rely on deer to survive, but fish also became an important food source for the predators over the summer of 2017. Tom Gable, a Ph.D. candidate from University of Minnesota, was hiking at a creek in April of 2017 when he spotted a wolf trying to catch a fish. It ran off into the woods, but the researcher saw fish remains and wolf tracks around the creek.

When they checked the activities of the wolf by tracking its location via its GPS collar, they found that the pack in Bowman Bay spent 43-63 percent of their time around the creek, hunting for fish.

The same behavior was also observed during spring this year, inspiring the team to set up cameras around the creek.

"The wolves are standing next to the creek in the dark, just listening or looking," said Gable. "You can see the wolves abruptly head to the water several times after hearing a splash — they learned what a fish splashing in the creek sounds like and they know that it means food. Incredible."

The Varied Diets Of Wolves

This is the first time that the behavior was captured on video. The researchers also found that wolves eat a lot of blueberries, primarily from July to August when the fruits are ripe in northern Minnesota and deer fawns are old enough to evade the predators. 

They also eat a lot of beavers, making up 42 percent of a pack's diet from April to October. On average, a wolf eats six to eight beavers per year. 

The findings were published in the journal Mammalian Biology. Watch the video footage below.