Study Shows Wolves Hunt Marine Mammals on Alaskan Coast

Spend some time in the Alaskan bush, and everyone’s got a wolf story: I’ve seen ’em grab salmon off waterfalls, or I watched a pack take down a brown bear. Now, researchers from the University of Oregon have published video evidence of something almost as surprising. In the summer of 2016, the research team filmed a wolf hunting down a harbor seal on the Alaskan coast in Katmai National Park.

In the 20-second video, a lone wolf can be seen wrestling with a seal in shallow, coastal water. The wolf continuously nips at the seal’s tail and walks circles around it looking for a way to make the final kill. According to the researchers, the struggle lasted about 30 minutes until the seal finally tired out and struggled to lift its head above the water. Then the wolf dragged it out onto a sandbar, tore into an existing wound on the tail, and began to chow down.

The wolf then noticed the researchers watching and ran away down the beach. It returned a few minutes later with another wolf, and the pair continued to eviscerate the seal.

The video is the first conclusive evidence of wolves actively hunting for marine mammals. But over the course of several years, the researchers documented wolves carrying sea creatures on numerous occasions. The first was in spring 2016, when Kelsey Griffin, a National Park Service biologist, was eating lunch on the beach. “Seemingly out of nowhere, we are sitting there, we just see this white wolf carrying an otter just trotting by,” Griffin said in an Oregon State University press release. “I was just blown away. I have never seen anything like that before.

The observation kicked off a more intensive research project involving camera traps and hours of observations. Among the things they discovered: a rocky, intertidal island that the wolves used to hunt sea otters.

The small outcropping is entirely submerged at high tide, but at low tides, sea otters haul out to rest on the rocks. While the researchers didn’t witness an active kill on the island, they were pretty darn close. The team watched three wolves disappear onto the island and return a few minutes later, dragging a sea otter. That afternoon, the team went to the spot where the wolves had subsequently consumed the animal and found only the remains of a few jaw pieces and the otter’s liver.

Intrigued by why the wolves had left the liver intact, the scientists sent it to a lab to be tested for paralytic shellfish poisoning—a deadly neurotoxin that can accumulate in shellfish-eating marine mammals. Their suspicions were confirmed when the results revealed elevated concentrations of paralytic toxins. In a paper published this summer in the journal Ecology, the researchers hypothesize that leaving the liver behind is a learned response to avoiding the potentially deadly toxins.

In terms of the bigger-picture implications of the team’s discoveries, Griffin said, “It kind of forces us to reconsider the assumptions that underlie a lot of our management decisions and modeling around wolf populations and populations of their prey, which often assume that wolves depend on ungulates, like moose and elk.”

It could also potentially have an impact on sea otter populations, which were historically decimated by the fur trade in the Katmai area. Their current population, however, numbers around 8,600 animals, thanks largely to protections first enacted in 1911. Regardless, the researchers were astute to have witnessed such a fascinating phenomenon and lucky to have caught it on film.

Feature image and video via National Park Service.

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