New Technology in Wildlife Tracking
A team of scientists in collaboration with Polar Bears International* just published a paper detailing a new type of GPS tracker to be used to monitor wildlife movements!
GPS data is invaluable in wildlife science for tracking individual animal movements, determining social behavior, determining a population’s response to new environmental factors, and more. Generally, scientists have relied on radio collars to transmit GPS data; this most commonly requires trapping and sedating an animal, then fitting them with a radio collar - and generally recording the animal’s vitals and taking a blood sample - then releasing them (for example: Johnson et al., 2017).
Photo Credit: Alaska Region US Fish & Wildlife Service, Flickr
While this is generally a safe and effective process, it is considered somewhat more invasive to the animal than other options, such as wildlife trail cameras or hair-snares. The hair-snare traps involve winding barbed wire around posts with bait in the middle, luring animals to the bait so that a hair sample can be snagged on the wire. Researchers can later collect the samples and, usually combining this data with videos from trail cameras, learn more about a wildlife population.
However, when researchers need data on animals’ movement across their environment, GPS radio collars are usually the most effective option for a variety of species. This is not the case for polar bears, though. Only female polar bears can be fitted with GPS radio collars, because the male bears’ necks are wider than their heads; this causes the collars to slip off, and, due to the lack of available methods for GPS data, has caused a knowledge gap in the movements of male polar bears (Ross et al., 2024).
Photo Credit: Wikimedia Commons
This is changing thanks to a recent study by Ross et al., in which researchers examine a new tracking technology called “burr on fur” on polar bears (2024). Researchers sedated the bears, which was done by remote injection after locating bears from a helicopter; after the bears were sedated, a GPS-enabled ear tag was attached to each bear along with one of three types of “burr on fur” trackers (Ross et al., 2024). The three varieties are the “pentagon tag (Argos Eartag Transmitter), the SeaTrkr tag (SeaTrkr GPS/ Iridium tag), and the “tribrush tag” (Ross et al., 2024).
Photo Credit: Ross et al., (2024). Telemetry without collars: performance of fur- and ear-mounted satellite tags for evaluating the movement and behavior of polar bears. Animal Biotelemetry, 12. Accessible caption text here.
These tags were secured to the bears’ fur, and the data they transmitted was compared with the data from the GPS ear tag to determine their accuracy (Ross et al., 2024). Then, researchers compared data from the “burr on fur” trackers to determine which type stayed attached to the bears the longest (Ross et al., 2024).
Ross et al. were even able to make assumptions about the bears’ behavior while the “burr on fur” tags were active; for instance, short step lengths and large turn angles” may correspond to foraging behavior, while “long steps and near-linear movement paths” may show a bear is in transit (2024).
Ultimately, researchers gathered “33,699 locations from 58 individuals equipped with ear or fur tags between 2016 and 2022,” for a total of “42 unique ear-tagged bears” (Ross et al., 2024). Of the three types of “burr on fur” tags, SeaTrkr lasted the longest at an average of 58 days, followed by tribrush tags, then pentagon tags (Ross et a.l., 2024). As these tags are designed to be used for short-term GPS monitoring, the duration of tag attachment was approximately as expected and allowed researchers to answer their study questions (Ross et al., 2024).
SeaTrkr tags were also “comparable [in] error resolution to conventional GPS collars,” making them a good candidate for collecting GPS data in the place of radio collars (Ross et al., 2024).
Photo Credit: NPS Climate Change Response, Flickr
Ross et al. were able to gain additional insights from this study, as well; they found that “bears travelled more as temperatures cooled” (2024). Additionally, they confirmed results of observational studies showing that “adult male polar bears limit their movements while ashore… spen[ding] approximately 70-90% of their time resting during the ice-free period” to conserve energy and fat storage (Ross et al., 2024).
Ross et al. recommend “further refinement and testing of fur tag designs,” but conclude that SeaTrkr “burr on fur” tags were the most effective design tested and can provide meaningful spatial and behavioral data (2024).
“These advancements will have tangible implications for wildlife management, aiding in tracking polar bears and promoting improved human-bear coexistence. We’re eager to further refine and deploy this pivotal technology.”
Geoff York, Senior Director of Research and Policy at Polar Bears International
A new type of GPS tracking technology, known as “burr on fur,” was studied by scientists to examine alternatives to GPS collars in collecting wildlife spatial data (Ross et al., 2024). Ross et al. found that SeaTrkr tags were the most effective “burr on fur” tag design, and were able to collect data on male polar bears, which had not been possible before this study due to limitations in GPS collar technology (2024). Ultimately, further testing will refine this design and provide wildlife scientists with new opportunities for collecting data on species movements and behaviors (Ross et al., 2024).
*Additional collaborations with/ contributions from “researchers from York University, the University of Alberta, Environment and Climate Change Canada, Manitoba Sustainable Development, Ontario Ministry of Natural Resources and Forestry, and Polar Bears International” (Earth.com).
References Cited:
Ross, T. R., Thiemann, G. W., Kirschhoffer, B. J., Kirschhoffer, J., York, G., Derocher, A. E., Johnson, A. C., Lunn, N. J., McGeachy, D., Trim, V., & Northrup, J. M. (2024). Telemetry without collars: performance of fur- and ear-mounted satellite tags for evaluating the movement and behavior of polar bears. Animal Biotelemetry, 12. https://animalbiotelemetry.biomedcentral.com/articles/10.1186/s40317-024-00373-2.
Johnson, H. E., Lewis, D. L., Verzuh, T. L., Wallace, C. F., Much, R. M., Willmarth, L. K., & Breck, S. W. (2017). Human development and climate affect hibernation in black bears with implications for human-carnivore conflicts. Journal of Applied Ecology, 55(2), 663-672. https://doi.org/10.1111/1365-2664.13021.
