A new study indicated that ancient polar bears made it through low ice periods by eating dead whales. However, according to the same research, carried out by the University of Washington and the University of Alberta, the present-day polar bears are not anymore able to achieve that.
“I don’t think we can assume what worked in the past is going to work in the future,” stated Kristin Laidre of the University of Washington.
About between 150,000 and 500,000 years ago ancient polar bears derived from other bear species, meaning that these animals went through several periods of low ice, the most significant one being approximately 130,000 years ago.
Kristin Laidre, the study’s leading author, and her co-author from the University of Alberta, Ian Stirling, hypothesized that the ancient bears survived periods of low ice by feeding on dead whales carcasses washed up on the Arctic ocean’s shores.
Ancient Polar Bears Survived Periods of Low Ice By Feeding On Dead Whales
“Polar bears likely survived those periods by accessing stranded marine mammal carcasses, and most likely large whale carcasses. They’re such large carcasses that they can be packages of food for, in some cases, years,” explained Kristin Laidre.
According to the new study, a population of approximately 1,000 ancient polar bears would have needed only about 20 bowhead whales carcasses to make it through the winter, while only eight such whales would’ve been required for them to survive during the summer.
Within a single stretch along the Russian shoreline of the Chukchi Sea, approximately ten dead whales carcasses a year are washed up between July and November. Even now, some polar bears learned to rely on that food resource in periods of poor seal hunting conditions.
“I think they [dead whales] were very likely the main source of nutrition” for ancient polar bears, added Ian Stirling from the University of Alberta.