Tracking Polar Bears: How and Why?

As an ecologist currently studying polar bear habitat and an ambassador for Polar Bears International, I get asked a lot of questions about my study species. Naturally, people are curious about what polar bear researchers do. But mostly, people wonder why we do what we do. One question I am often asked is why we require location data, especially when the methods, such as attaching a collar or an ear tag to a polar bear, can appear restrictive or even negatively impactful. I always try to explain how beneficial this data is to the conservation of the entire global population of polar bears, but also that the methods are not harmful at all.

First, any scientist hoping to study wild animals requires wildlife research ethical certifications. Each of the five polar bear countries (Canada, the United States, Denmark, Norway, and Russia) has different governing bodies that grant these certifications. For example, in Canada, animal welfare in study situations is monitored and protected by the Canadian Council on Animal Care (1). In the United States, this is governed by the Committee on Animal Research and Ethics (2) and in Denmark, by The Danish Animal Ethics Council (3).

Because I study and volunteer within a Canadian context I’ve focused on Canadian ethical standards and research methods throughout this post. Getting certified for this kind of research in Canada requires an extensive application process that includes explicit explanations of the field techniques used (1). The review and approval process can take months and once approved, certificates must be updated every year. In short, the health and welfare of wild animals is the most important component of this kind of research. Remember, we do what we do because we care about conserving polar bears—we’re not going to put any bears in jeopardy for the sake of science.

Historically, it was more common to use satellite radio collars to collect polar bear location data. Until recently, it was the only technique we had. These collars weigh less than a couple of kilograms, compared to an average adult female polar bear weight of 200-300 kg (4), and are designed with a release mechanism that causes them to fall off within a couple of years (5). If for some reason a collar malfunctions and does not, we can find and remove it manually because we know the approximate location of the bear. Recently, because of advances in technology, we can attach a much smaller and lighter device to the bear’s ear (6). New technology is constantly being developed, such as Polar Bears International’s burr on fur study (7), to provide even less invasive ways of collecting data (5). Each of these methods have no proven negative side effects on the bears (4).

All methods involve sedating the bear. A large predator is not going to allow us to get close to it without putting up a fight. Sedation protects both us and the animal from harm. To sedate polar bears, scientists find individuals via helicopter and dart them with a tranquilizing gun from the air (8). In Canada, the drug used (Telazol) is approved by the Canadian Association of Zoo and Wildlife Veterinarians as the ideal sedative to use on polar bears due to how fast-acting and effective it is and because no negative effects occur (8). At a minimum, the helicopter houses the pilot and a trained biologist or veterinarian who are trained in wildlife sedation to ensure best practices are used (9). After successfully sedating the animal, the helicopter lands and the hands-on work commences. Because the bears are unconscious, there is no irritation or pain associated with attaching the device. Proper protocols require that we monitor their vitals, such as heart rate and temperature, to ensure that the individual is well and not experiencing any negative effects of the drug or field techniques used (8). Once the field work is complete, scientists stay nearby to ensure that the animal shows signs of recovery from the sedation; if possible, they also often go back to check on the animal later in the day (9).

But what is location data and why is it necessary to collect?

The collars or ear tags we attach to these bears are known as satellite telemetry devices. They are essentially battery-powered GPS devices. In other words, they transmit data to a satellite that tells us which bear the data is from and where the individual was at the time of transmission. Historically, collars could be programmed to transmit high resolution location data six times a day for a two-year duration, while ear tags currently transmit lower resolution data once a day and only for six months (9). The higher resolution of the collars therefore gives us more robust datasets. Interestingly, because male polar bear necks are so muscular, they are wider than their heads, meaning that collars slip right off (10). Thus, researchers have historically only been able to collect collar data for female polar bears. It was only when ear tags were developed that we were able to begin tracking the movement of males. There are pros and cons, scientifically, to the different types of devices used.

Since polar bears occur in low densities across vast landscapes, using their location data is really the only effective way to study them. We simply cannot sit and observe their behavior or movements like we can for smaller or less mobile species (4). Without this data, we would have never known that there are 19 different subpopulations of polar bears—it was significant differences in their movement that told us this (4). We would also have no idea where exactly these bears are at what time of the year. This data allowed us to understand that polar bears in some parts of the world (such as in Churchill, Manitoba) spend time on both land and sea ice, but they do so during different times of year (4,11). Knowing this allowed us to then ask ourselves why. By comparing this data to environmental data, such as satellite sea ice imagery, we were able to understand that polar bears follow the sea ice throughout the year (2). This may be intuitive now because we all understand how connected polar bears are with their sea ice environment, but we didn’t always know this. Before we were able to collect this data, we could only speculate on the behavior of these bears. Now, we understand how interconnected the relationship is between polar bears and Arctic sea ice. With more recent data, we now also understand that polar bear movements have begun to shift with changing sea ice conditions brought on by climate change (2).

Scientists also use polar bear location data for novel and exciting research. For example, studies using telemetry data have been used to estimate the abundance of bears in each geographic area, allowing us to gain a better understanding how many polar bears exist (4). This data has also been used to identify important denning habitat for female polar bears (2), allowing us to protect these bears during the most vulnerable time in their lives (12). Because we know ideal denning habitat for some subpopulations, we can then predict it for others for which we lack this data (4). In addition, during the process of fitting collars or ear tags to polar bears, scientists take body measurements and tissue samples (4). Together with the location data, this information has been used to understand how movement or habitat use can influence the health or diet of polar bears (4). It allows us to understand how healthy or unhealthy these bears are—and with their habitat melting across the Arctic, you can imagine how vital this information is to their conservation.

In the future, we will continue to use this data to further understand the influence of climate change on these vulnerable bears (2). We could use it to design protected areas or improve human protection by estimating areas where human-bear conflict may arise (4). Clearly, this data has the capacity to tell incredibly important stories. Without it, we would not be working towards protecting the polar bear, because we would never have understood that they needed protecting in the first place.

Larissa Thelin is an MSc student at the University of Alberta, studying under Dr. Andrew Derocher. She is also an ambassador for Polar Bears International. Her research focuses on polar bear space and habitat use in relation to changing sea ice conditions and the presence of their prey.

Citations

1. Canadian Council on Animal Care. (n.d.). About the CCAC. 2. American Psychological Association. (n.d.). Committee on Animal Research and Ethics (CARE). 3. The Danish Animal Ethics Council. (n.d.). The Danish Animal Ethics Council. 4. Laidre, K., Durner, G., Lunn, N., et al. (2022). The role of satellite telemetry data in the 21st century conservation of polar bears (Ursus maritimus). Frontiers in Marine Science. 5. Polar Bears International. (n.d.). How do the collars come off? In Frequently Asked Questions. 6. Polar Bears International. (n.d.). Are collars the only way to track polar bears? In Frequently Asked Questions. 7. Polar Bears International. (2020). Wild polar bears test new tracking tech. 8. Stirling, I., Spencer, C., & Andriashek, D. (1989). Immobilization of polar bears (Ursus maritimus) with Telazol in the Canadian Arctic. Journal of Wildlife Diseases, 25(2): 159-168. 9. Dr. Andrew Derocher (Polar Bear Biologist, Department of Biological Sciences, University of Alberta). Personal Communication, June 2022. 10. Polar Bears International (Dec 7, 2020). Wild polar bears test new tracking device. 11. Polar Bears International. (n.d.). Why are polar bears collared? In Frequently Asked Questions. 12. Polar Bears International. (n.d.). Den Research.