Alaska’s gray wolves have started hunting sea otters along the coast, and scientists still do not know how they are catching them

On the rugged coastline of Prince of Wales Island, Alaska, something is happening that has caught scientists genuinely off guard. Gray wolves — land predators built for forests and open terrain — have been observed hunting sea otters, a marine species still clawing its way back from near-extinction.

It’s a predator-prey dynamic few researchers expected to witness in the modern era. And while the evidence that wolves are killing and eating sea otters is no longer in doubt, how exactly they’re pulling it off remains an open question.

A predator crosses into unfamiliar territory

Prince of Wales Island sits in the Alexander Archipelago of southeastern Alaska — remote, densely forested, edged by cold Pacific waters. It’s not the place you’d expect to find wolves wading into the surf after marine prey. Yet that’s exactly what researchers are documenting here.

Patrick Bailey, a Ph.D. candidate at the University of Rhode Island, is leading the first focused scientific effort to study this behavior. His work starts from a striking observation: gray wolves on this island aren’t just scavenging the occasional dead otter washed ashore. They’re actively hunting and consuming sea otters — a species still classified as endangered following its near-elimination during the fur trade era.

That classification matters. Sea otters are a protected, recovering population. Any new predation pressure carries real ecological weight, and it forces researchers to rethink a foundational assumption — that wolves are strictly terrestrial hunters.

What wolf teeth reveal about a changing diet

To understand how deep this behavior goes, Bailey is turning to an unexpected source of evidence: wolf teeth. Teeth grow in layers over time, much like rings inside a tree trunk — each one a biological record of what the animal was eating during that stretch of its life.

Using stable-isotope analysis, Bailey samples individual growth rings from wolf teeth collected from museum collections and recently deceased animals. The technique lets him trace dietary shifts across an animal’s lifetime — from inland prey to marine species, or the reverse. “If large enough, we can individually sample each of these growth rings to track an individual’s feeding patterns over time,” he explains. By analyzing enough specimens, researchers can assess how widespread marine feeding actually is.

There’s a deeper question lurking here too. Sea otters were nearly wiped out by the fur trade. As their populations slowly recover along the Pacific Coast, wolves may simply be resuming a predator-prey relationship that existed long before colonial-era hunting disrupted it — something the isotope record might eventually confirm.

Trail cameras set to capture the hunt itself

Knowing wolves are eating sea otters is one thing. Understanding how they catch them is a separate problem entirely.

Earlier footage of wolf hunts in coastal environments lacked the resolution needed for detailed behavioral analysis. Bailey addressed this directly during fieldwork last summer, installing new trail cameras positioned to capture close-up hunting behavior on Prince of Wales Island. A team of seven University of Rhode Island students is currently working through more than 250,000 images collected since December — painstaking work, but the potential payoff is significant.

“What hasn’t been explored, and what I am really interested in documenting, is how exactly wolves are able to capture sea otters,” Bailey says. Sea otters spend much of their time in the water, an environment wolves aren’t built for. Whether coastal wolves have developed specific behavioral adaptations to bridge that gap is something the cameras may finally help answer.

Mercury moving up the food chain

The ecological stakes extend well beyond predator-prey dynamics. There’s a toxicological dimension researchers are only beginning to understand.

Sea otters accumulate high concentrations of methylmercury — a toxic compound that moves up the food chain as predators consume contaminated prey. Wolves eating those otters absorb that mercury load too. Liver samples from coastal gray wolves on Prince of Wales Island show mercury concentrations up to 278 times higher than those found in inland wolf populations. That’s not a marginal difference.

“Methylmercury accumulation can cause a suite of problems related to reproduction, body condition, and behavioral abnormalities,” Bailey explains. This toxic transfer is an unintended cost of a dietary shift that, on the surface, might look like simple ecological opportunism.

Bridging land and sea ecosystems

Wolves are already recognized as powerful shapers of terrestrial ecosystems. Their presence — or absence — can cascade through an entire food web, affecting vegetation, prey behavior, and even river systems. Bailey suspects similar ripple effects may extend into aquatic habitats when wolves begin feeding at the ocean’s edge, though that remains an open hypothesis rather than a settled conclusion.

Could wolf predation slow the pace of sea otter population recovery? Researchers don’t yet have an answer, but it’s one of the threads Bailey’s work is actively pulling on.

The project has depended heavily on local expertise. Alaska Department of Fish and Game biologist Gretchen Roffler and field technician Michael Kampnich have been central to its success. Bailey is direct about their contribution: “This project would not be possible without their input and guidance.” Kampnich, in particular, has helped the research team navigate the island’s challenging terrain — knowledge that years of outside study simply can’t replicate.

Looking ahead, Bailey plans to expand the research beyond Alaska. A separate dissertation chapter will compare skull morphology between coastal and inland wolf populations, drawing on specimens from parts of Canada — including Newfoundland and Labrador — held at the Harvard Museum of Comparative Zoology. He also plans to return to Prince of Wales Island next summer, with data collection expected to span several more years.

The wolves were here long before anyone was watching closely. Scientists are only now beginning to catch up.