Ocean STEMulation: Tracking Polar Bears by Satellite
Focusing on different aspects of science, technology, engineering, and math, as they pertain to the ocean.
The Arctic is a challenging place to do research, and polar bears are difficult and dangerous to approach. While there are still many unanswered questions about polar bears, our understanding of them has come a long way since the 1970s when scientists started using satellite tags to study them.
A satellite tag transmits a signal to a network of satellites that send data to scientists. Polar bears were one of the first animals tracked in this way but this method is now used to study many animals, from birds to sea turtles.
A researcher examines a sedated bear’s feet in 1982. Photo by NOAA Photo Library, Flickr, Creative Commons License.
After sedating a polar bear, scientists can safely work with it. In addition to putting on a collar with the satellite tag, which is designed to fall off after 14 months, scientists measure the bear’s size, take blood samples, examine teeth and collect other data. (Only female polar bears can wear collars because males’ necks are thicker than their heads, so the collar would slide off.) Before long the bear will wake up and continue on its travels – but now scientists can follow it by satellite!
One of the earliest satellite collars used to track polar bears. Photo by United States Department of the Interior, Fish and Wildlife Service, “Satellite Telemetry: A New Tool for Wildlife Research and Management,” 1988.
Satellite tracking data is important for various reasons. In one extreme case, scientists followed the journey of a bear and her cub who swam 420 miles, never finding sea ice and returning to land nine days later. It was the longest recorded swim by a polar bear and it took a toll: she had lost more than a fifth of her body weight, and her cub did not survive.
This bear was sedated, tagged and moved over 60 km outside of Churchill, Canada, before being released. Photo courtesy MacGillivray Freeman Films.
Tracking also reveals travel and denning habits, such as when a mother enters and exits her maternity den, or where a bear prefers to hunt. Researchers can also compare the growing and shrinking sea ice to the paths of the bears to see how the animals respond to the changing habitat.