Alaska’s gray wolves have started hunting sea otters in the ocean, wading into marine waters to chase prey they were never known to pursue, and scientists are only beginning to understand what that means

On the rocky shoreline of Prince of Wales Island, Alaska, something quietly unprecedented is playing out. Gray wolves — built for forests and tundra, hardwired to chase deer and moose — have started wading into the ocean to hunt sea otters. It’s a behavioral crossover that no one predicted, and researchers watching it unfold say they’re still far from understanding how it works.

The strangeness isn’t lost on the scientists tracking it. An apex land predator pursuing a marine mammal in its own element raises questions that existing wildlife research simply wasn’t designed to answer.

A predator crossing the shoreline

Gray wolves on Prince of Wales Island have been documented preying on sea otters — a fully marine mammal — in what researchers describe as a rare behavioral shift. Official sightings of wolves consuming aquatic prey stretch back more than twenty years, though the behavior has only recently attracted systematic scientific attention.

Patrick Bailey, a Ph.D. candidate at the University of Rhode Island, leads the investigation alongside his advisor Sarah Kienle at the CEAL Lab. Their focus isn’t simply confirming that this is happening. The deeper puzzle is how — sea otters are agile, ocean-adapted animals, and catching one is nothing like running down a deer through a forest.

That distinction matters enormously. A land hunt plays to every advantage a wolf has: speed, endurance, coordinated pack movement across familiar terrain. Pursuing a sea otter into open water strips most of those advantages away. Whatever these wolves are doing at the shoreline, it represents a genuine departure from the predatory playbook their species has followed for thousands of years. 

Where land and sea food webs collide

Researchers suspect that connections between marine and terrestrial food webs are far more common and complex than previously recognized. On land, wolf predation creates cascading effects across entire ecosystems — shifting where prey animals graze, how vegetation recovers, even how rivers run. Bailey and his colleagues are now asking whether similar ripple effects could reach into coastal marine environments.

The stakes aren’t abstract. Sea otters were nearly wiped out by the fur trade during westward colonial expansion and remain classified as endangered. Their slow recovery along the Pacific Coast is one of conservation’s more hopeful ongoing stories, and wolf predation introduces a variable that no one had planned for — one that could complicate that fragile comeback in ways still difficult to model.

This may also be the reopening of something ancient, according to A-Z Animals. Before the fur trade collapsed otter populations, wolves and otters shared coastlines for millennia. That predator-prey dynamic didn’t disappear so much as get interrupted. Now, as otters return, it may simply be reasserting itself. 

Reading wolf teeth like tree rings

To understand how long this behavior has been occurring — and how widespread it really is — Bailey turned to an unlikely source: wolf teeth. Using stable-isotope analysis on specimens from natural history museums as well as recently deceased animals, his team can reconstruct individual dietary histories over time.

The method works because wolf teeth, like the growth rings inside a tree trunk, build up in distinct layers. Each layer captures a chemical record of what the animal was eating during that period of its life. “If large enough, we can individually sample each of these growth rings to track an individual’s feeding patterns over time,” Bailey explains. Mapping this data across multiple animals could reveal whether sea-otter hunting is a widespread behavioral adaptation or an isolated anomaly — with museum specimens offering a window into historical diets that predates any researcher’s presence on the island.

Quarter-million photos and still no clear answer

Despite decades of sightings, the actual mechanics of how wolves catch sea otters remain entirely unknown. Past video footage of wolf hunts was too blurry to analyze, leaving the most basic question unanswered.

Bailey installed new high-resolution trail cameras over the summer specifically to capture clearer evidence. Since December, those cameras have collected more than 250,000 photos — a massive archive now being reviewed by seven University of Rhode Island students. Whether the images contain the answer is still an open question.

Local expertise has been essential throughout. Gretchen Roffler, a biologist with the Alaska Department of Fish and Game, and technician Michael Kampnich have contributed knowledge that outside researchers simply can’t replicate. “Working with locals is so important because they have decades of experience and perspective that we as outside researchers simply do not have,” Bailey says.

A hidden cost: mercury in the food chain

The behavioral shift carries a consequence that no one anticipated. Sea otters accumulate high concentrations of methylmercury — a potent neurotoxin — through the marine food chain, and wolves eating those otters are absorbing it too.

Liver samples from coastal wolves show methylmercury levels up to 278 times higher than those found in inland wolves. Researchers warn this could affect wolf health, reproduction, and potentially long-term behavior, though the full implications remain under study. Whether elevated mercury levels will eventually discourage coastal hunting, or whether wolves will continue regardless of the physiological cost, is still unknown.

What comes next for wolves on the coast

Bailey plans to extend the research beyond Alaska. By comparing historical skull specimens from Newfoundland and Labrador with those from elsewhere in Canada and the United States, he hopes to examine morphological differences between coastal and inland wolf populations — asking whether living near the ocean is physically reshaping wolves across generations.

As sea otter populations continue recovering along the Pacific Coast, the wolf-otter interaction is likely to intensify. More otters mean more opportunity, and potentially more wolves learning to exploit it. Researchers increasingly view the Alaska case as a model for studying how top predators adapt when their traditional food sources shift. The wolves on Prince of Wales Island may be early movers in a pattern that coastal ecosystems across North America will eventually have to reckon with.