Scientists studying polar-bear hearing; research could affect oil drilling

SAN DIEGO — Shikari is making that huffing sound polar bears make when they're checking out their surroundings.

The 12-year-old, 550-pound Ursus maritimus is also eyeing the four humans watching her from behind steel bars. Her thick, black nose is twitching with the scent of her visitors.

But most important, Shikari is listening — listening to tones being generated by a computer. Her small, rounded ears perk up as each tone is sounded.

When she hears a tone, she has been trained to press her nose on a pad. Through the bars, researcher JoAnne Simerson gives her a tasty brownish morsel called "omnivore chow."

It's all for science.

Shikari and her twin sister, Chinook, are part of the first-ever study of polar-bear hearing. The project began in September at San Diego Zoo, in cooperation with SeaWorld.

With the oil and gas industries looking to explore and expand drilling activity in Alaska, researchers want to discover what the noise from such exploration would do to polar bears, particularly females who are pregnant or nursing cubs.

Funding for the study, up to $60,000, comes from BP, formerly known as British Petroleum. The Louisiana-based conservation group Polar Bears International acted as middleman for the grant.

While the study is being underwritten by the oil industry, researchers say they are not taking sides on the issue of expanding oil drilling in Alaska. The findings will be printed in a scientific journal next year.

"It behooves both sides of the argument to know what the reality is," said Megan Owen, a lead researcher with the zoo's Conservation and Research for Endangered Species facility. "We're just gathering the data."

Polar bears are the world's largest land-based carnivores, but knowledge about them is spotty, researchers said.

It's known that a polar bear can smell a seal 20 miles away and can swim at speeds up to 6 mph, but estimates of their hearing capacity are largely guesswork.

"We know almost nothing about the hearing of bears, great cats and ungulates [hoofed animals]," said Ann Bowles, bio-acoustic specialist at the Hubbs-SeaWorld Research Institute. "We're in a state of blankness."

Polar-bear specialists estimate that upward of 25,000 polar bears roam the Arctic and that about 2,000 of them live near the North Slope oil fields. The federal government is evaluating a request from a conservation group to list the polar bears as a "threatened" species, one step away from "endangered."

Since the early 1960s, the government has insisted on a 1-mile buffer zone between oil drilling and areas where polar bears congregate.

"We've retained [the 1-mile rule], but we don't know how effective it is," said Scott Schliebe, a polar-bear specialist with the U.S. Fish and Wildlife Service based in Anchorage.

As development pushes into areas where female polar bears give birth, the 1-mile limit takes on added significance.

"It was really just an arbitrary decision to put it at one mile," said Steven Amstrup, polar-bear specialist with the U.S. Geological Survey, also based in Anchorage. Amstrup is an expert in the polar-bear maternity den sites in Alaska's Arctic National Wildlife Refuge.

Depending on what the hearing research finds, he said, the 1-mile rule may have to be changed.