Polar bears were found to increasingly swim life-threatening long distances due to a variety of reasons, headlined by climate change, a new study has found.
While ice melting due to global warming in the polar regions may be tagged as the main reason for the polar bears changing its swimming distances, other factors may also play a role.
The findings of the study confirmed the hypothesis that long-distance swimming by polar bears are due to climate warming, but the extent of the effects differs within and between populations, pointing out to other things at play.
"Migratory responses to climate change may vary across and within populations, particularly for species with large geographic ranges," the authors write.
Being Solitary
Polar bears are known to be solitary. When it comes to migratory behavior, the species tend to manifest individual variations, as opposed to other group-living species.
In the study, the researchers found that migratory responses to changing climate and subsequent sea ice condition alterations vary within populations, suggesting distinctive migration, which may include the differential distances.
Body Size
Body size may play a role in the distance and duration of lone polar bear swims during migration, the study suggests.
In the past, experts have suggested that body size is a notable factor in influencing the patterns of migration of other species. This is because animals with big body size have lower energetic transportation cost for every unit of body mass. The results of the new study reflect this and support the relationship.
Change Of Seasons
The difference in the swim distances of polar bears may also be attributed to the season. During spring, polar bears in Beaufort Sea like to hunt seals when there is active ice thus, they select locations near the shorefast ice boundary.
Polar bears may possibly extend their stay on the continental shelf, where there are abundant supplies of seals.
When the ice breaks up, it becomes mobile hence, polar bears need to swim between glaciers more frequently.
During summer, when polar bears stay on the sea ice, the species are able to gain more energy either due to seal killings or by having early access to seals during autumn when the ice moves back to the shelf.
Cub Protection
Adult females that aim to protect their cubs also exhibit varied patterns in swimming distances. As per studies, long-term exposure to extremely cold water may have detrimental effects to offsprings. With this, females try to avoid areas with open water during the spring, explaining why they have their own pattern of swimming migration.
