Past Studies

From enrichment studies for zoo polar bears to wild-polar bear behavior research on a remote Russian island, our completed projects add to our understanding of the world's polar bears:

Human Impact
Western Hudson Bay Dens
Wrangel Island
Stereotypic Behavior
Estrous Cycles
Whisker Pattern
Nutrition Study/Association of Zoos & Aquariums (AZA)
International Polar Bear Husbandry Conference

Human Impact Study
What effect do noisy tourists and tundra vehicles have on polar bears? Results from our two-year study, led by Dr. Jane Waterman, now serve as guidelines for ecotour operators.

Sound and flurries. The team:

• Conducted approach experiments to determine at what distance, if any, polar bears are bothered by tundra vehicles.
• Studied how polar bears react to the average noise levels produced by tourists.
• Ran the same experiments, with the same bears, on consecutive days to see if the bears become accustomed to the activity.

Slow and steady. The scientists found that most responses occurred when a vehicle approached:

• Closer than 50 meters
• Too quickly
• Directly towards a bear

These findings confirmed what Tundra Buggy® drivers had already discovered on their own: that they could avoid disturbances by controlling the distance, angle, and speed of an approach. 

Finally, the team concluded that polar bears quickly habituate to tourist vehicles and human-induced sounds. Five male bears observed the first year didn't respond at all the next!

Western Hudson Bay Dens
Most female polar bears dig snow dens to give birth, but the bears in the western Hudson Bay population, which is farther to the south, choose dens in the peat banks along rivers. But that area is drier now due to climate change and more prone to fires caused by lightning strikes. What effect will this have on the bears?

Three strikes. This study by M.S. Candidate Evan Richardson, working with Dr. Ian Stirling, looked at the effect of forest fires on polar bear maternal den sites, which are traditionally used year after year. The scientists:

• Compared the physical characteristics of 48 burned and 101 unburned dens in western Hudson Bay.
• Found that fire significantly altered the vegetation, resulting in unstable den sites, the collapse of dens, and the degradation of the surrounding habitat.
• Confirmed that female bears looking for den sites did not use burned areas.

Harder on polar bears. Because these dens are traditionally re-used, increased search times for suitable den sites and the need to dig new dens could affect reproductive success. Forest fires are expected to increase with climate change, leading to further loss of suitable denning habitat in the area. The scientists recommended that management authorities increase firefighting efforts in the area .
                                                                       
Wrangel Island
For more than a decade, PBI funded Dr. Nikita Ovsyanikov's polar bear research on Russia's Wrangel Island, where he lived and worked among the great white bears, observing social behavior. He also monitored their health and condition, along with changing sea-ice coverage.

Polar bear rules of order.  Although polar bears are usually solitary animals, they sometimes gather in one place. This happens when they're forced ashore by melting ice or find a bountiful food source like a whale carcass.

This project has added to our understanding of:

• How polar bears form congregations.
• How newcomers join established groups.
• Spatial distribution in groups, which is governed by sex, age, and class. For example, mothers with cubs find a place to rest or nurse away from the adult males.

Personality factor. Just as with humans, personalities vary in polar bears. Some adult males are shy. Some females are forceful. In stable congregations, however, there is very little actual aggression. Most of it is displayed by mothers making lunges at bears—both male and female—who come too close to their cubs.

Large white males. Large adult male polar bears have the highest rank in the social order. They go where they please and take what they want. Other findings:

• Large older females usually dominate younger animals. In encounters with young males their rank is not as certain—it depends on personalities. 
• Among subadult bears, males dominate females. Young females are usually more cautious and are the first to leave a problem encounter.
• Among very young bears, cubs who have mothers to protect them rank higher than orphaned or abandoned cubs living on their own. 

This hierarchy is not set in stone, however: A furious mother can drive away a huge male.

Social bonds. Almost nothing is known about the strength of social bonds between individual polar bears in the wild, but there is some evidence that on a personal level bears may form strong bonds. These alliances include:

• Male-male bonds in social congregations: these bears  behave like good friends, traveling together, playing together, and staying close to each other. 
• Family groups, including mothers with cubs of different ages.

Solitary hunters. Despite the polar bear's social nature, polar bears never hunt in teams, as wolves and other social canids do. However, they will share prey. Ovsyanikov observed as many as eight bears peacefully eating from the carcass of a young walrus, standing shoulder to shoulder, adults together with cubs. Even more striking, the sharing took place among bears who were not related. 

Conclusion. The polar bear's high intelligence is a useful tool not only in the complicated, constantly changing environment of the drifting Arctic sea ice, but also in managing personal interactions within a social community. 
                                                                  
Stereotypic Behavior
Three years. 20 zoos. 55 polar bears. This ground-breaking study was the first to take a comprehensive look at repetitive behavior in polar bears in zoos—and to document ways to change it. The results? Some zoos have reduced pacing and other stereotypic behavior by 95%. Now that's something to shout about.

Dr. David Shepherdson, a research scientist at the Oregon Zoo in Portland and a well-known animal behaviorist, conducted the study for PBI. He examined:

• Factors that lead polar bears to pace or swim in repetitive patterns.
• The effects of exhibit designs.
• Enrichment items that encourage good health and reduce stress.

Shepherdson monitored the bears for three years. He measured blood cortisol levels to gauge stress responses. He also assessed the behavior and temperament of each bear.

Want to learn more? We've gathered his key findings here.
                                                                             
Estrous Cycles
How many estrous cycles occur in polar bears? How long is each cycle? And why should we care?

Polar valentines. Dr. Tom Spady, a reproductive physiologist, studied the polar bear's breeding cycle as part of a team working at the San Diego Zoo. His findings are important because we may be left with remnant populations of wild bears as the sea ice continues to shrink. A boost of genetic diversity from zoo bears may help these survivors repopulate the Arctic if the sea ice returns.

• In the meantime, the knowledge gained is helping zoos:
• Notice if a zoo bear has a problem, since ovarian cycles are an early indicator of reproductive health
• Develop effective birth control for polar bears in zoos
• Know when to introduce males and females for natural breeding
• Know when to separate bears
• Apply assisted reproductive techniques more effectively
• Notice if a zoo bear has a problem, since ovarian cycles are an early indicator of reproductive health

The study is yet another example of how research with captive bears may benefit their wild counterparts. 

Whisker Pattern Study
How do scientists tell polar bears apart? In the past, scientists  traditionally relied on capture-recapture efforts to identify individual bears. But a PBI-funded study by Dr. Jane Waterman, a PBI Research Scientific Advisory Council member, confirmed that polar bear whisker spot patterns can also provide reliable IDs—especially for field work conducted close to the bears.

Say seals. The method is simple:

• Take a digital photo of the polar bear's profile, ideally from less than 50 meters away
• Super-impose a grid over the image to map out the whisker spot pattern
• Use that pattern to ID the bear

Just like fingerprints. Waterman and her team found that each polar bear has a unique whisker spot pattern that can confirm the bear's identity. This quick and easy, non-intrusive method is especially well-suited for behavior and population studies in places like Churchill where polar bears gather.
                                        
Nutrition Study/Association of Zoos & Aquariums
Polar bears mainly eat seals in the wild, but what they should eat in zoos? When PBI hosted the International Polar Bear Husbandry Conference in 2004, we quickly realized that members of the zoo community had a number of questions related to diet.

Blubber or carrots? To fill this need, we brought together nutrition experts from zoos, led by Barbara Lintzenich (Cincinnati Zoo), chair of the American Zoo Association's Nutrition Advisory Group and team director of the project. They produced a comprehensive manual on the nutritional needs of captive polar bears. The 66-page document covers:

• Dietary needs of polar bears in zoos
• Feeding methods that provide psychological stimulation
• Sample menus

For your copy, click here.
                                                                              
International Polar Bear Husbandry Conference
PBI organized and hosted this international conference in 2004 as a way to bring together experts from the zoo and wild bear communities. Such a cross-disciplinary gathering had never been held before for any species.

We organized the conference so the two groups could:

• Meet and interact with each other.
• Share information and points of view.
• Discuss research needs and find ways to help each other.

It's all about polar bears. Over 50 speakers from around the world helped stimulate discussions. The various captive-wild polar bear research initiatives PBI has since funded are a direct result of the conference. Click here for the complete proceedings.





                                                                              
Our Thanks
To Dr. Jane Waterman and Dr. Jim Roth of the University of Central Florida (UCF) and M.S. candidate Gillian Eckhardt for conducting the Human Impact Study. The team received logistical support from Tundra Buggy Adventure® and Hudson Bay Helicopters.

To Evan Richardson, then M.S. candidate at the University of Alberta, and Dr. Ian Stirling of the University of Alberta and the Canadian Wildlife Service for the Western Hudson Bay Den Study.

To Dr. Nikita Ovsyanikov for research efforts on Wrangel Island, Russia, and to Dr. David Shepherdson of the Oregon Zoo for his Stereotypic Behavior Study.

To Dr. Thomas Spady for his work on the Estrous Study, then with San Diego Zoo's Center for Reproductive Research (CRES). And t to JoAnne Simerson, trainer and animal behaviorist at the San Diego Zoo, for training the bears.

To Carlos Anderson, then an M.S. candidate at UCF, for field work and analysis on the Whisker Pattern Study under the direction of Dr. Jane Waterman and Dr. Jim Roth.

To Barbara Lintzenich, chair of the Association of Zoo & Aquarium's Nutrition Advisory Group (NAG) and team director of the Nutrition Study. Four other main authors include Ann Ward (Fort Worth Zoo), Dr. Mark Edwards (National Zoo), Dr. Mark Griffith (Purina Mills), and Dr. Charlie Robbins (Washington State University). Kerri Slifka and Krista Jacobsen of the Brookfield Zoo contributed.