Polar bears have become a face for climate change as the world has increasingly become aware of the challenges they face. The International Union for Conservation of Nature (IUCN) classifies polar bears as vulnerable, one step above endangered. In 2008, the U.S. Fish and Wildlife Service listed polar bears as threatened under the Endangered Species Act. Other areas of the world, such as Russia and Canada they are considered red listed or species of special concern. Regardless of their classification, the greatest threat polar bears are facing is habitat loss due to climate change. Polar bears rely on the Arctic sea ice to hunt seals, their primary prey.
As climate change continues to be a pressing issue, it is important we understand the effects it has on polar bear populations. However, polar bears are notoriously difficult to study in the wild. They have large home ranges in a harsh environment, making them difficult to find. Once a bear is found, in order to collect samples and data, the bears must be tranquilized from a helicopter. This is an expensive process and can be a risky procedure for the bears. Considering these circumstances, polar bears in human care provide an excellent population for research and gathered data can be used to inform conservation efforts on their wild counterparts.
Polar bears under managed care in Association of Zoos and Aquariums (AZA) institutions participate voluntarily in research projects. Caretakers work tirelessly with the animals, using positive reinforcement to encourage these voluntary behaviors that will allow for research participation. In addition, opportunistic sampling (such as fecal or blood samples) provides an excellent source of data. Many of these studies are conducted in conjunction with Polar Bears International (PBI) or the U.S. Geological Survey (USGS). Continue reading for some examples of how captive polar bears are providing data to help us understand their wild counterparts.
Sensory Studies
It can be difficult finding love in the harsh landscape of the Arctic. To understand how polar bears find each other, a collaborative study between PBI, USGS, and AZA aimed to see if polar bears leave scent markings behind in their pawprints and if the polar bears can distinguish between male and female pawprints. During routine mark-and-recapture work, scientists collected swab samples from polar bear paws. These swabs were then presented to polar bears in zoos to see if they could distinguish between the scents. Indeed, the project showed the polar bears spent more time investigating the scents of opposite-sex polar bears. This pattern was particularly striking in the spring, the polar bear mating season. It seemed as though males could distinguish the smell of a female bear in estrus. This study raises concerns about polar bears being able to find each other to mate in the wild. If sea ice is also serving as a messenger board for polar bears, the increased disappearance of the ice could make it more difficult for bears to find each other to mate.
Along the Northern Slope of Alaska, concerns were raised over how the noise from oil and gas activities could effect mother polar bears in their dens. As polar bears den in the snow, it is difficult to observe what is occurring in those dens. In response to these concerns, AZA institutions set out to conduct a study on polar bear hearing. The participating bears were moved into a sound-dampened space for the study and were trained to casually move their head in response to a specific sound. From the study, the researchers learned that polar bears have approximately twice the hearing range as humans. The information collected provides valuable insight into how to protect polar bears from industrial disturbances, particularly during denning season.
Accelerometer Studies
Tracking polar bears using satellite collars provides information about hunting patterns, habitat use, and total distance traveled by a bear. Additionally, scientists use accelerometers to track polar bear movements and activities (similar to how a Fitbit tracks your activities). However, the data from these accelerometers are difficult to understand. Again, scientists turned to captive bears for help. By placing collars on bears in zoos and observing them, the scientists were able to discern what the data mean and interpret the behavior of wild bears, even from thousands of miles away. Anthony Pagano from the USGS explains the study in this video:
Interested in tracking a polar bear? Check out PBI's polar bear tracker. You can see the routes taken by wild bears throughout the Arctic!
Reproduction Studies
Polar bear reproduction is not well understood and quite tricky. Their breeding is seasonal, and they undergo delayed implantation. If mating is successful, an embryo will form, but only grow to a size of about 400 cells, about the size of a grain of sand, and stop growing. The embryo floats around in the uterus during the summer months, then implants into the uterus to finish developing once the days start to shorten. The Cincinnati Zoo and Botanical Garden is pioneering research through their Polar Bear Signature Project aimed at understanding polar bear reproductive physiology. Goals of the project aim to develop a polar bear pregnancy test, develop assisted reproductive technologies (such as artificial insemination), and understand sexual maturation in polar bears. By studying captive bears to learn about their reproduction, scientists can gather valuable information that will be critical for understanding the reproductive health of wild polar bears. Dr. Erin Curry explains briefly the goals of the project in this video:
Additional Resources
To learn more about the research being done to protect polar bears, visit Polar Bears International's website.
PBI also has excellent tips on how you can get involved and help protect polar bears in the wild.
To learn more about the AZA's involvement in polar bear research, check out these links:
Thanks for reading! Have a question about zoos, conservation, research, or animals? Let me know by filling out the form below and we'll learn together! You can also follow me on Twitter (@samantha_vold).
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