nullResearchers are tagging walruses to learn more about them. Image: USGS

In September 2009, a team of biologists flew over the remote Alaskan beach of Icy Cape on a reconnaissance mission. Thousands of Pacific walruses had reportedly broken from their normal habits and shambled onto the shore there, and the scientists were keen to observe their behavior. But they didn't find an unruly mosh pit of jostling animals—the walruses had moved on, leaving behind only a scattering of small carcasses on an empty beach.

"We found over 100 dead baby walruses," says Tony Fischbach, a biologist with the U.S. Geological Survey's walrus research program. The dead youngsters didn't show any signs of disease, says Fischbach: "They were all fat little sausages."

In three of the last four summers, thousands of walruses have mysteriously come ashore in Alaska. This unprecedented behavior occurred when ice in Chukchi Sea drastically retreated, leaving the marine mammals without their usual summertime habitat. Alaskan scientists aren't the only ones who have noticed: Climate change activists have already adopted the walrus's cause, and the U.S. Interior Department is now deciding whether to list the walrus as endangered species. But in the midst of all this hustle, Fischbach and his colleagues are struggling to determine whether the changing climate poses a serious threat to the species' survival.


Carrie Goertz, a veterinarian with the Alaska Sea Life Center, was part of the crew that flew out to examine the dead walruses last year. Of the 62 animals that they examined, 60 were under a year old. "We found hemorrhaging," she says. "Our conclusion was that they died from being trampled." Walruses don't usually gather in huge numbers, but in these strange new Alaskan "haul-outs" the animals clump together in the thousands. If a young calf gets separated from its protective mother, Goertz says, it could easily be squashed by the herd.

The USGS researchers published a report (pdf) on the findings, but their work was far from done. After all, plenty of young walruses die each year on the sea ice, and Pacific walruses have come ashore on Russian beaches in past decades during their fall migrations. How could the scientists determine whether the summertime Alaskan haul-outs signaled a new, existential threat to the species?

The answer: By virtue of some extraordinarily challenging fieldwork.

"Walruses are fundamentally difficult to work with," says Fischbach in a resigned voice. "They range across a vast region that crosses international boundaries, the environment is inhospitable to humans, and it's expensive and difficult to get out there. It's far away from home—even just to buy a gallon of Coleman fuel to run your stove, it's about $25 per gallon." And then there's the difficulty of getting access to the animals. "About 80 percent of the time they're in the water, and that means they're feeding," says Fischbach. "That means they're at the bottom of the sea for seven minutes, then they pop up to breathe, and then they do it again."

To learn about the everyday lives of these difficult creatures, Fischbach and his colleagues have been attaching satellite tags to walruses—a difficult operation in itself, requiring the biologists to land a helicopter downwind of the herd, then slowly wriggle forward on their bellies until they can fire a tag into an animal's thick skin.

The tags have two simple sensors—one pressure gauge, and one saltwater detector—which together allow the researchers to determine how much time the walruses are spending in the water, and at what depths. The tags break down after two to three months, but that's enough time to compile extensive "walrus diaries" that the researchers are eager to read.