Polar Bears at San Diego Zoo Undergo
Hearing Study

Acoustic sensitivity research may impact protection offered wild bears

Researchers from the San Diego Zoo's center for Conservation and Research for Endangered Species (CRES) are currently collecting data to determine the hearing sensitivity of polar bears, a fundamental aspect of the bears' biology that is currently unknown. Determining how sensitive polar bears are to various tones and frequencies may help wildlife management agencies in the Arctic establish guidelines to protect the bears' from potentially harmful industrial noise. This is the first study of its kind with any bear species.

Worldwide industrial practices threaten polar bears in a variety of ways, from exposure to environmental toxins and the imminent threats of global warming to increased pressure to tap petroleum reserves in the Arctic region. The International Union for the Conservation of Nature (IUCN) recently upgraded the polar bear's status to "vulnerable," increasing their need for conservation efforts.

According to the acoustic sensitivity study's lead scientist, Megan Owen, some of the most promising, and hotly debated petroleum reserves in the United States are located in Alaska's North Slope region. This coastal plain is also a primary denning site for the southern Beaufort population of female polar bears where they give birth and rear their young. This population is the largest concentration of female polar bears in the United States.

"Extracting petroleum involves a great deal of heavy industrial machinery and activity, but nobody knows how disturbing this industrial noise is to the bears. Information on the hearing spectrum of the bears will aid wildlife management agencies in establishing parameters and guidelines to protect the bears from disturbances," Ms. Owen explained.

The initial phase of the study involves behavioral testing of two adult female polar bears at the San Diego Zoo. Each bear is called into a sound-dampened room where they have been trained to station in a specific location. The bears listen and then respond when they hear a sound emitted from a computer by touching their nose to a small wooden target, indicating to their keeper that they have heard the sound.

"All the training has been accomplished using positive reinforcement techniques," explained the study's lead trainer, JoAnne Simerson, from the San Diego Zoo. "The system and technique is very similar to human hearing tests. Polar bears are incredibly intelligent animals and love to be challenged to learn new things. They have learned to listen for the tones and respond very quickly."

According to Megan Owen, conducting research of this kind would be impossible with wild polar bears, but the controlled environment of the Zoo, coupled with professional animal keepers and cooperative bears, make this study feasible. The goal of the initial phase of research is to obtain 1,000 hearing trials per bear over the next several months, after which the study will be conducted at other institutions housing female polar bears. Adult female bears are the primary focus for the first phase of study because denning females on the Alaskan North Slope are potentially the most susceptible to industrial noise.

 "We are collaborating with Hubbs-SeaWorld Research Institute bioacoustics specialists and Polar Bears International to create the methodology for testing the hearing spectrum of bears. The goal is to be as flexible and versatile as possible so that the animal training techniques, sound-dampening materials, and configuration can be used at other zoological institutions with other polar bears to enlarge the database of information," said Ms. Owen.

The goal for CRES researchers is to have the research methodology honed, data collected and compiled, and initial results available by late next year.

More

Hearing Sensitivity of the Polar Bear with Implications for Environmental Disturbance in the Wild
Watch the Zoo's polar bears daily on Polar Cam.
Read a blog by Megan Owen, Can You Hear Me Now?