On Alaska’s remote Prince of Wales Island, gray wolves have developed an unexpected hunting habit: they’re preying on sea otters.
This surprising shift in diet could reshape both marine and land ecosystems, but scientists are only beginning to understand what it means—and how the wolves are managing to capture such elusive marine prey.
Patrick Bailey, a Ph.D. candidate at the University of Rhode Island, is leading one of the first studies to document this rare behavior.
Using wolf teeth samples, stable isotope analysis, and thousands of trail camera images, Bailey and his team are trying to piece together how coastal gray wolves hunt sea otters and what this adaptation reveals about their evolution.
“Wolves are known to dramatically shape land ecosystems,” Bailey said. “But we don’t yet understand how they might influence marine ecosystems. Since wolves can have such powerful effects on land, it’s possible we’ll see similar patterns in coastal environments.”
Sea otters were nearly wiped out during the fur trade centuries ago but have made a slow recovery along the Pacific coast.
As their populations grow, wolves may be reviving an ancient predator-prey relationship. To trace this interaction, Bailey analyzes growth rings in wolf teeth—each layer preserving chemical clues about the animal’s diet at different times in its life.
“If we have enough samples, we can track an individual’s diet over time and even see population-wide patterns,” he explained.
Capturing marine prey like sea otters requires completely different skills than hunting deer or moose on land. Bailey and his advisor, URI scientist Sarah Kienle, suspect these coastal wolves have evolved new hunting strategies. “We’re really curious to see how they do it,” Kienle said.
Although reports of wolves eating marine animals have existed for decades, no one has clearly documented how they hunt them—until now.
Bailey has installed high-resolution trail cameras across the island to try to catch the behavior in action. His team, including seven URI students, is currently reviewing more than 250,000 images of wolf and otter activity gathered since last winter.
The research isn’t easy. Wolves are intelligent, secretive, and live in rugged, remote terrain. Bailey credits his success to close collaboration with local experts, including Alaska Department of Fish and Game biologist Gretchen Roffler and research technician Michael Kampnich, who know the island’s ecology better than anyone.
“Working with locals is crucial,” Bailey said. “They have decades of knowledge we simply don’t have.”
One emerging concern is mercury contamination. Roffler’s work has shown that sea otters in the area carry high levels of methylmercury—a toxic form of mercury that can build up in predators.
Wolves that eat sea otters have been found with mercury levels hundreds of times higher than those living inland, raising questions about the long-term effects on their health, reproduction, and behavior.
Bailey plans to continue his fieldwork over the next several years, expanding his study to compare coastal and inland wolf populations across North America. He’s also examining skulls from historical East Coast wolves to understand how diet and environment may have shaped their evolution.
For now, he hopes next summer’s field season will bring a breakthrough: the first clear footage of gray wolves hunting sea otters in the wild—a glimpse into one of nature’s most unexpected and little-known predator relationships.
