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- Between 2012 and 2022, researchers studied two populations of polar bears (Ursus maritimus) in the high Arctic. They tranquilized several bears to record their age, sex, reproductive status and health.<\/li>\n
- During the health checkups, the scientists observed various injuries on the bears\u2019 footpads, including cuts, hair loss, skin ulcerations and ice buildup. In two severe cases, the adult bears had thick ice blocks, 30 centimeters (1 foot) in diameter, stuck to their paw pads and surrounding fur, causing deep, bleeding cuts. \u201cThe two most-affected bears couldn\u2019t run \u2014 they couldn\u2019t even walk very easily,\u201d lead author Kristin Laidre, a scientist at the University of Washington, U.S., said in a statement. \u201c[T]he chunks of ice weren\u2019t just caught up in the hair. They were sealed to the skin, and when you palpated the feet it was apparent that the bears were in pain.\u201d<\/li>\n
- The researchers write that such injuries \u201chave not been observed during previous research in these areas or reported in the scientific literature.\u201d The scientists also interviewed 22 Indigenous subsistence hunters from the region who said they, too, had not observed such injuries until recently.<\/li>\n
- The study\u2019s authors speculate that the warming Arctic could be contributing to the bears\u2019 paw injuries. Increased rain-on-snow events, when rain falls on existing snow, causes snow to melt more quickly. Wet snow could be clumping on the bears\u2019 paws, then refreezing into solid balls of ice as temperatures fall. Warming is also causing the surface snow to melt, then refreeze into hard crust when the temperature drops again. Heavy polar bears, while walking, might be breaking through the crust and slicing their paws on the sharp edges. Local hunters reported similar conditions lead to paw injuries in their sled dogs.<\/li>\n<\/ul>\n
Why it matters<\/h2>\n
The researchers say they\u2019re unsure how the injuries will affect polar bear populations, but they speculate the injuries could reduce the bears\u2019 \u201cability to hunt and travel successfully.\u201d<\/p>\n
Recent research suggests the Arctic is warming nearly four times faster than the global average. Winter warming and rain-on-snow events have also been increasing as a result, the authors write. Continued warming will likely create \u201cchallenging surface conditions for polar bears to travel on\u201d and make the polar bears, which are considered vulnerable to extinction, more prone to injuries, they add.<\/p>\n
Three adult polar bears travel across sea ice in eastern Greenland. Image courtesy of Kristin Laidre\/University of Washington.<\/figcaption><\/figure>\n