Polar Bears Aren’t Getting Enough To Eat Since Sea Ice Is Dwindling

As sea ice dwindles due to climate change, polar bears living in Western Hudson Bay are struggling to get enough to eat, leading to a decline in their population.
Researchers from the University of Toronto Scarborough concluded that the population decline is the result of bears not being able to find food since shrinking sea ice is causing shorter hunting seasons.
“A loss of sea ice means bears spend less time hunting seals and more time fasting on land,” said Louise Archer, the lead author of the study.
“This negatively affects the bears’ energy balance, leading to reduced reproduction, cub survival, and, ultimately, population decline.”
The research team developed a model that tracks the amount of energy bears are currently receiving from hunting seals and the amount of energy needed for them to grow and reproduce.
The model follows the full life cycle of individual polar bears from cub to adulthood. It also compares four decades of data from the Western Hudson Bay population of polar bears between 1979 and 2021. During this period, the region’s polar bear population dropped by almost 50 percent.
In addition, the average size of polar bears is in decline. The body mass of adult females has decreased by 86 pounds and one-year-old cubs by 47 pounds. The trend will continue to happen if the region keeps experiencing the loss of sea ice.
“Our model goes one step further than saying there’s a correlation between declining sea ice and population decline,” said Péter Molnár, a co-author of the study and an associate professor in the Department of Biological Sciences at the university.
“It provides a mechanism that shows what happens when there is less ice, less feeding time, and less energy overall. When we run the numbers, we get a near one-to-one match to what we’re seeing in real life.”

Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
The researchers noted that cubs are the most affected by these climate-related issues. The shorter hunting periods cause mothers to produce less milk, threatening the cubs’ survival. If cubs fail to gain enough weight, they face reduced rates of survival.
Mothers are having fewer cubs as well. According to data, litter sizes have declined by 11 percent compared to nearly 40 years ago.
The cubs are also staying with their mothers for longer because they are not strong enough to live independently.
Western Hudson Bay has long been viewed as an indicator of polar bear populations worldwide. As the Arctic continues to warm four times faster than the global average rate, the researchers warn that other polar bear populations will face similar declines.
“There’s every reason to believe what is happening to polar bears in this region will also happen to polar bears in other regions, based on projected sea ice loss trajectories. This model basically describes their future,” said Molnár.
The study was published in Science.
More About:Animals