Thousands of young Pacific walruses were trampled to death by stampedes in the Arctic this past summer, due to the fast-melting sea ice.
According to a report in the National Geographic News, this year, northern sea ice retreated faster and farther from the shoreline than ever recorded—well beyond the shallow waters. This caused the giant herds of the stranded walruses to panic and stampede into the water, thus causing the deaths of several thousands of the mammals.
The hungry animals were then forced to clump together on land instead. "They came ashore in places that we hadn't seen before and in numbers that in many cases were considerably larger than we'd ever seen before," said Bruce Woods, a spokesperson for the U.S. Fish and Wildlife Service in Anchorage, Alaska.
The crowding was particularly acute on the Russian side of the Bering Strait, according to Russian biologists who collaborate with the U.S. Fish and Wildlife Service. These biologists counted about 3,000 to 4,000 walrus carcasses along the coast in the areas they surveyed, which was higher than normal. "But the loss is not a major blow to its population," said wildlife service experts.
"Like any herd animal, walruses are easily spooked, Loud boats, low-flying airplanes, or the sight of predators such as polar bears cause them to panic and rush toward the water," Woods told National Geographic News. "Particularly when their numbers are so great, sometimes walruses are hurt or killed in stampedes, and the ones that tend to be hurt or killed, of course, are going to be the smaller animals," he added.
According to Woods, if the sea ice continues to shrink—as climate models suggest it will, there will be additional impacts.
"The Pacific walrus likely warrants protection, though scientists currently lack sufficient data on the species' habitat and population size compared to species such as polar bears," said Kassie Siegel, an attorney and climate change campaigner for the Center for Biological Diversity in Joshua Tree, California. "It's not that the species is necessarily at less risk," Siegel said. "It's just that we don't know as much about it," she added.
Walruses feed on clams and other bottom-dwelling creatures in the shallower waters along the coasts and usually rest on ice floors between meals.