Rising temperatures and shrinking habitat are forcing the polar bears to move to the far north of Canada where sea ice is plentiful and thicker. The two main problems which are causing the furry animals to move further up north are lack of suitable conditions and the instability prevailing in the eastern and southern parts of the Arctic.
Scientists belonging to the United States Geological Survey have been analyzing the genetic construction of polar bear populations and observed that an increasing number of these animals are inching towards the Canadian archipelago. This migration towards colder regions, according to them, started in the 1990s and the trend dates back to three generations of these animals now.
While talking to Alaska Public Radio Network (APRN), a wildlife biologist with USGS, Lily Peacock, said, “Instead of sort of random movements of bears across the Arctic that we found in sort of the more ancient historical picture, we found directional movement towards the Canadian Archipelago”.
Instead of simply tracking the movements of these animals with the help of satellites, the researchers based their observations on a genetic analysis of a large number of polar bears. This included collecting blood samples from them, among other things. This genetic analysis has also shed light on the past story of mating and movement of these animals and a lot more, including the rise and fall in their numbers.
“By examining the genetic makeup of polar bears, we can estimate levels and directions of gene flow, which represents the past story of mating and movement, and population expansion and contraction. Gene flow occurs over generations, and would not be detectable by using data from satellite-collars which can only be deployed on a few polar bears for short periods of time,” said Peacock in a press release.
“And what can happen when populations of animals become isolated is that they can blink out if something happens. If they have a bad winter or bad spring and that stresses the population and it gets smaller and smaller, but the migration corridor has been cut off and you can’t repopulate.”
The findings of Peacock and her colleagues which were first published in the journal PLOS ONE are being hailed as being highly reliable because of the methodology involved in collecting the data.