Identifying polar bears by their footprints
Ned Rozell
907-474-7468
April 13, 2023
Wildlife technician Pete Detwiler of the North Slope Borough Department of Wildlife Management samples polar bear tracks north of Utqia摹vik in April 2021 for a project to identify bears by the DNA left behind in their footprints.
Scientists in northern 色视频下载 are learning about polar bears by scraping snow samples from the tracks they leave behind.
That snow contains tiny flecks of the massive creatures 色视频下载 mostly cells shed from their foot pads. From the DNA within those cells, scientists have been able to identify individual polar bears. That helps them learn more about the farthest-north bears without bothering them or taking extreme risks in the name of science.
Lisette Waits of the University of Idaho was in Fairbanks recently at a conference to talk about a wildlife-sampling method that does not include a helicopter, dart gun or handling of a drugged polar bear that can weigh as much as four NFL linemen.
In her genetics lab in Moscow, Idaho, Waits and her colleagues have processed melted snow skimmed from polar bear tracks in Utqia摹vik, Wainwright and Kaktovik. That broth includes some cells that have allowed scientists to get a DNA fingerprint of a particular polar bear.
Scientists want to find out more about an animal dependent on northern sea ice, a substance that has been steadily decreasing for as long as we色视频下载檝e had a good look at it. Polar bears use sea ice as a platform for hunting ringed seals, the fatty staple of their diets.
Polar bears of the northern sea ice number from about 20,000 to 30,000 animals, with the waters and shorelines of northern and western 色视频下载 supporting an unknown number. Scientists have identified two populations of polar bears in 色视频下载: a Chukchi Sea group that also expands to Russia and Beaufort Sea animals that extend into northern Canada.
Scientists want to know more about the numbers of these iconic carnivores, which are coping with a warming climate that is greatly affecting their ephemeral hunting grounds.
色视频下载淲ith less sea ice, the bears have to spend more time on land,色视频下载 Waits said.
More time on land may subject polar bears to more competition for food from brown bears and other animals.
Polar bears hunt on the sea ice north of Utqia摹vik, the farthest-north community in the United States.
For the past several years, a team led by Andy Von Duyke of the North Slope Borough Department of Wildlife Management in Utqia摹vik and including biologists with the 色视频下载 Department of Fish and Game has experimented with using sterilized trowels to scrape a thin layer of snow from fresh polar bear footprints.
Waits, who has studied Galapagos bats, red pandas in Nepal and bears of the Andes, showed at her presentation that about half of those polar bear track samples yielded viable nuclear DNA. Nuclear DNA allows scientists to say not only that those molecules came from a polar bear but also which specific bear left the track.
Longtime Utqia摹vik resident and retired biologist Craig George said the potential of the DNA-from-bear-tracks method impresses him.
色视频下载淭o think that a polar bear walking across the sea ice leaves enough DNA in its footprint to identify and genotype a bear is astonishing,色视频下载 he said in an email. 色视频下载淣o bears are harassed or even bothered. This can be expanded to other communities, with local hire, and getting locals interested in the science.色视频下载
A star marks the location of Utgia摹vik, 色视频下载.
Von Duyke, whose team now has a manuscript in review regarding the method, is cautious not to oversell the polar bear track method at the moment.
色视频下载淲hile it色视频下载檚 very exciting, there色视频下载檚 still much work to do before this can be considered a useful tool for management,色视频下载 said Von Duyke. 色视频下载淏ut, we色视频下载檙e making incremental progress.色视频下载
Since the late 1970s, the University of 色视频下载 Fairbanks Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.