The Fall Of The Walrus

WHY ARE THE WALruses killing themselves? In the last week of August, 70 two-ton bulls climbed to the top of a cliff above Maggie Beach, a remote and forbidding area in southwestern Alaska. One by one, the huge and ungainly mammals waddled over the eddge and fell 100 feet onto the rocks below. It was the third consecutive year that walruses plunged to their death on this beach--and scientists still can't explain why.

For as long as humans can remember, every summer walrus bulls "haulout" along the beaches of Bristol Bay to sun and feed themselves in anticipation of the long winter ahead. The giant herds--there are an estimated 12,000 bulls--congregate in a corner of the Togiak National Wildlife Reserve; together they form the largest concentration of walruses on the North American mainland. Until the fall of 1994 the walruses were content to lounge along the sandy shore. Then one day, says Togiak Reserve manager Aaron Archibeque, a fierce storm struck the cape, and some of the animals retreated up a bluff in search of shelter, or so scientists thought. Perhaps disoriented or unsteady on rain-slickened grass, 42 of the bulls fell over the edge of the cliff. During another storm in October 1995, 17 more died.

But this year, the walruses began climbing the bluff late on a clear, moonlit night. The next morning, two biologists with the U.S. Fish and Wildlife Service camping at a field station near the beach noticed the migration. They managed to turn back 1150 bulls, Archibeque says, but 70 reached the top where almost all plunged to their death. Such behavior among walruses has never been documented before, Archibeque says. "We're still trying to figure out why this is happening." One theory: a sand dune that once blocked access to the cliff is no longer there, worn down by the walruses and the violent storms that often strike the area. Once at the top, the walruses may simply get too close to the edge to turn around. "It's a real herd response, just like with caribou or lemmings," says Dana Seagars, a scientist with the Fish and Wildlife Service. "Once the first one falls, it is too late for the second or third or fourth to turn around."

Could the walruses be committing mass suicide? Marine biologists emphatically reject that idea as misguided human projection. "That is anthropomorphizing," says Seagars, who prefers to call the wal- rus plunges "an unusual mortality event." Alaskan Eskimos, for whom walrus meat is the principal staple, are just as puzzled as the scientists. "I really don't know what makes them go up the cliff, " says Isaac Tuday, mayor of the small nearby fishing village of Togiak. Should humans intervene to prevent the annual immolations? A barrier could be built to prevent the walruses from making their deadly climb, Seagars says. "There have been intense debates about whether interfering with nature is the right thing to do," he says. "But it's very difficult to watch natural selection at work."