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 edge 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. 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 150 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. "It’s a real herd response," says 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 anthropomorphising," says Seagars. 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.\ It is certain that the walruses
A．climbed the bluff in search of shelter from a fierce storm in the fall of 1994. B．fell off the edge of the cliff in the fall of 1994 because they got lost. C．plunged to their death in the fall of 1994 for the first time in history. D．fell off the edge of the cliff in the fall of 1994 because of rain-slickened grass.