According to the findings of a new study, the population of the polar bear in the Arctic region is declining at a fast rate due to climate change.
The thinning of Arctic sea ice is making the bears unable to catch enough prey to meet their energy needs. The study was published in the journal called ‘Science’.
Key Highlights of the Study
• The study revealed that polar bears have higher metabolic rates than previously thought and that the climate change is affecting their environment for hunting prey.
• The study also shows that some of the bears are losing weight at a time when they should be gaining.
• The study reveals that due to global warming the arctic ice is shrinking, which is making it harder for the bears to catch their prey during their prime hunting time.
• The ice cover in the Arctic grows in the winter and melts in the summer. However, due to climate change, the ice is shrinking and thinning more than ever.
• Researchers have been studying polar bears in the Beaufort Sea area since the 1980s.
• Their most recent population estimate indicates the polar bear population has declined by about 40 per cent over the past decade.
• The US Fish and Wildlife Service lists polar bears as a threatened species.
• This study identifies the mechanisms that are driving those declines by looking at the actual energy needs of polar bears and how often they are able to catch seals.
• The Polar bears hunt from the ice. They often wait for seals to pop out of holes to get air and at other times they swim after seals.
• If there is less sea ice and it is broken apart, bears have to travel more or swim more, which has serious consequences such as more energy use, hypothermia and risk of death.
• The researchers monitored the behaviour, hunting success, and metabolic rates of adult female polar bears without cubs as they hunted for prey on the sea ice of the Beaufort Sea, outlying sea of the Arctic Ocean, in the spring.
• High-tech collars on the bears recorded video, locations, and activity levels over a period of eight to 11 days, while metabolic tracers enabled the team to determine how much energy the bears expended.
• The field metabolic rates they measured averaged more than 50 per cent higher than previous studies had predicted.
• Five of the nine bears in the study lost body mass, meaning they were not catching enough fat-rich marine mammal prey to meet their energy demands.
• Global warming in the Arctic means that the sea ice is breaking up earlier in the summer and returning later in the fall, forcing bears to spend more time on land and travel much greater distances than previously.
• This causes them to expend more energy during the summer when they are fasting until the ice returns to the continental shelf in the fall.