Polar bears are no dummies. According to a recent study by zoologist Elizabeth Peacock of the U.S. Geological Society, polar bears and at least some other arctic animals are trying to adapt to climate-related changes in their habitat (such as losses of sea ice) by migrating northward.
Researcher Elizabeth Peacock suggests polar bears will go with the flow
“In general, polar bears move with their habitat,” explained Peacock. Her study on arctic migrations was published in the most recent issue of the journal PLOS ONE.
“Sea ice is like a moving sidewalk and they travel with it,” she added. “Bears likely move towards places with better access to prey and mates.”
Polar bears need sea ice to survive, Peacock said, because the animals use it as a platform to access seals for prey, as well as for migration, mating and denning. They need ice or they have to swim greater distances in the open water. If stuck on land, polar bears sometimes enter a state of “walking hibernation” and stop eating.
In general, “the longer the ice-free period,” she said, “the longer the time without feeding.”
Arctic animals migrating north
According to Peacock’s research, polar bears have been gradually moving north toward the Canadian Archipelago over the past 15 to 45 years.
The researchers identified four genetically similar clusters of polar bears by their primary location: Eastern Polar Basin, Western Polar Basin, Southern Canada and the Canadian Archipelago. Using a sophisticated DNA analysis, they found there is directional gene flow toward the bears living in the Canadian Archipelago.
Other arctic animals are also moving north. “There are a number of other Arctic species that have shifted distributions with loss of sea ice,” Kristin Laidre of the University of Washington’s Polar Science Center recently commented to Discovery News.
Walruses that typically gather on sea ice have been seen in massive groupings on beaches in northern Alaska during recent months, she said.
She pointed that reduced sea ice has also made it possible for bowhead whales to move across the Northwest Passage separating Alaska and Greenland. Melting ice has also allowed beluga whales to winter in new areas close to Greenland. Other ocean researchers have observed that killer whales are moving into the Arctic earlier in the winter and are usually staying longer.
“In some cases,” Laidre explained, “species are seeking the sea ice because their life history is linked to the ice. For example, they need ice for giving birth, for feeding, resting, etc.”
“When the ice is absent,” she added, “they must shift to land, and in other cases, the sea ice recession is opening up new habitat that allows animals to move into areas they have not been able to occupy before.”
