ANCHORAGE -- For years, conventional wisdom has advised people to make noise to avoid dangerous surprises while traveling in Alaska bear country. For those who choose not to talk, sing, clap or bang on a cook pot, that usually means wearing bear bells, a tried-and-true hiker's accessory.
But do the bells really work, or work the way we think they do? Though he emphasizes that it's too soon to draw any broad or definitive conclusions, Tom Smith of the U.S. Geological Survey's Alaska Science Center has tested a group of brown bears that seemed to pay bells no mind at all.
Over several days last fall, while doing other research about bear behavior along the coast of Katmai National Park, Smith hid in a blind near a well-traveled bear path and pulled on fishing line attached to a string of bells tied to an alder bush. Not one bear looked in the direction of the noise or even perked up its ears, Smith said.
``This doesn't mean bear bells don't work,'' he said. ``It just means the bears didn't respond the way we thought they would. Not one of them reacted to the bells at all. It's fascinating stuff.''
Smith said he first tinkled the bells lightly. The bears didn't respond. Then he yanked on the line, making a jangling noise ``almost as loud a fire alarm.'' Fifteen groups of one or more bears walked past. Not one flinched.
He didn't think the bears were deaf, but he wondered. So he snapped a pencil to mimic the sound of a twig breaking. The bears immediately turned and looked at the biologist's blind, about 150 feet away. A loud huff, mimicking the noise of another bear, elicited a similar response.
The lack of reaction to the bells doesn't prove anything, Smith said. Other factors could have contributed, including a relative lack of aggressiveness in Katmai bears compared with other Alaska grizzlies.
Still, the results are intriguing enough that Smith wants to investigate further.
He emphasized that it is premature to tell people to stop wearing bear bells. They certainly might help in some circumstances, he said. Bears in some places might learn to associate bell sounds with humans, he said.
Smith spends most of his time studying brown bear behavior and bear-human interactions. Along the way he has made some observations that have led him to take a closer look at long-held assumptions about how bears see, hear and smell.
He is the same researcher who discovered two years ago that pepper spray, sold as bear repellent, can attract bears if used improperly. In effect, he found that the bears seemed to like the taste or smell if the repellent was sprayed on the ground or an object, not directly in the face.
Because brown bears are naturally curious, Smith thought they would approach the bells to investigate. Why would they ignore them? Maybe, he said, bears tune out tinkling just as they might tune out other nonthreatening background noises, like birds singing or a stream gurgling.
This summer, he plans to do a more thorough study. If he gets funding, he plans to put out a recording of different noises - human voices, a dog barking, snoring, acoustic guitars, pots and pans - at various decibel levels to learn more about how bears react. He also wants to try his experiment on other bear populations in the state.
Not a lot of research has been done on bears and bells, he added, and some of it is confusing. A 1982 study in Glacier National Park in Montana pointed out that the only people who were charged by bears were not wearing bear bells. The same study also said that people wearing bells observed bears at a much closer distance than people not wearing bells.
If Smith's hunch is right, it would upset some of the prevailing advice about how to avoid bears: Make noises not found in nature to warn bears you are coming.
Most Alaska guidebooks offer identical advice about hiking in bear country: Talk, sing, shout, rattle pebbles in a can, bang on a pot or wear bells. Helen Nienhueser, co-author of ``Fifty-Five Ways to the Wilderness in Southcentral Alaska,'' one of the state's best-selling hiking guidebooks, said she uses bells when hiking alone. Some hiking guides prefer talking and singing for hiking in places where it's hard to see or be seen.
Nienhueser said she started using bells more often while hiking to her cabin south of Denali State Park after a woman and her son were killed at McHugh Creek just outside Anchorage five years ago.
``I'd be disturbed if they don't register hearing bells,'' she said.
Jim Holmes, who staffs the public information counter at the Alaska Department of Fish and Game in Anchorage, said he fields bear questions all day. He gives people advice similar to what appears in guidebooks: Make a lot of noise or wear bells.
``Bells are a 100 percent sure thing,'' Holmes said. ``Everyone will agree that a lot of bear attacks occur because someone surprises the bears. If a mama bear hears bells, that's not birds singing or water gurgling.''