A new study reports that polar bear cubs have a higher mortality rate as their icy habitat melts. As their habitat melts away at faster rates than before polar bear cubs alongside their mothers are forced to make longer trips swimming across the icy waters, leading to an increase in death rates.
According to Reuters, the new study shows that these long distance swimming trips pose great risks to the survival of polar bear cubs. Polar bears are not aquatic animals. In fact, the majority of their lives are spent on ice or land–where they hunt, feed, and give birth.
In order to conduct the study, researchers attached 68 polar bear females with GPS collars, and used satellites to track their movement over a six-year period from 2004 to 2009. Using the collars they were able to track when the bears were forced to swim over 30 miles during one trip.
According to the Daily Mail, the study concluded the bears performed 50 long-distance swims over the six-year period. Researchers say the swims included 20 different polar bears swimming distances of 426 miles and lasting up to 12.7 days.
The study concluded that polar bear cubs that didn’t have to swim long distances with their mothers had an 18 percent mortality rate. Scientists speculate there are two main reasons why the bears are struggling to survive. One major reason being that polar bears, unlike humans, are not able to close their nasal passages. Therefore, when they hit rough waters they have a hard time avoiding taking in water.
Another reason the cubs are having trouble relates to their body fat content. The Daily Mail reported that Steve Amstrup, a former scientist at the U.S. Geological Survey and chief scientist at Polar Bears International, said “Young bears don’t have very much fat and therefore they aren’t very well insulated and cannot cope with being in cold water for very long.”
Polar bears are considered an endangered species in North America. This is the result of greenhouse gases building up in the atmosphere melting the bears icy climate.