Melting icebergs cause trouble for walrus populations
Aug 19, 2011
Polar bears aren't the only mammals affected by the melting arctic. Walruses have been moving to shore earlier than usual this year, causing conservationists to worry about stampede deaths among the young when trampled by adults, the Anchorage Daily News reports.
Traditionally, walruses dive into shallow arctic waters for mollusks, clams and other animals, resting on drifting sea ice between food dives during the summer. Because these icebergs are disappearing in these places and because the animals cannot dive deeper, they retreat into land near shallower waters, CBS News reports.
As a result, the crowds of walruses congregate in groups of as many as 40,000, causing stampedes that kill hundreds of the animals, mostly calves. The carcasses attract polar bears. Plus, the larger and earlier-than-normal masses strain the local ecosystem, the news source reports.
The arctic sea ice has been retreating for about 30 years, and reached a record low in 2007, according to the media outlet. The U.S. National Snow and Ice Data Center reported that this year, the sea-ice extent is low, and may even fall below levels recorded in September 2007.