Polar Bear/Grizzly Hybrids Could Become More Common Due To Climate Change

The curious polar-grizzly hybrid known as “pizzly” or “grolar bear” could become much more common as the climate warms.

A “pizzly” at Osnabrück Zoo, Germany. Photo: Corradox

The accelerating climate crisis appears to have an unexpected effect on Arctic wildlife, with global warming causing an overlap between the hunting grounds of two of the region’s apex predators, grizzlies and polar bears. Instead of fighting each other, however, the two species seem to be more into some “opportunistic mating”, IFLScience reports.

The resulting hybrid bear has occurred both in captivity and in the wild. In 2006, the occurrence of the grizzly/polar bear hybrid in nature was confirmed by testing the DNA of a unique-looking white bear sporting brown patches, shot near Sachs Harbour, Northwest Territories on Banks Island in the Canadian Arctic. According to Wikipedia, the number of confirmed hybrids has since risen to eight, all descending from the same female polar bear.

A grolar bear in the wild. Photo: Source

Arctic climate change poses a serious threat to polar bears (Ursus maritimus) as global warming reduces sea ice, which means fewer opportunities for the animals to prey on juicy seals resting on top of icebergs. As a result, they are forced further south out of their hunting zones in search of food. This means that polar bears, which are particularly adapted to a diet of high-fat blubber and meat, may potentially have to alter their diets and consume foods they are not well suited for, according to a study published in Global Change Biology.

Warming temperatures, on the other hand, are pushing grizzly bears (Ursus arctos) north, continuously increasing the chance of contact with polar bears.

“We’ve known about pizzlies for quite some time, but their occurrence may be more common with ongoing Arctic warming,” explains Larisa DeSantis, associate professor of biological sciences at Vanderbilt University and co-author of the study, in the video below.

As mentioned in the video, second-generation hybrids have also been sighted. Ulukhaktok airport in Canada’s Northwest Territories famously greets visitors with a stuffed pizzly that is 3/4 grizzly and 1/4 polar bear. In 2017, a study traced eight known grolar bears back to one female polar bear that had mated with two grizzly bears.

And indeed, DeSantis states in the video that the two species are capable of reproducing offspring that are themselves capable of reproducing (most hybrids are sterile) as the two species only diverged around 500,00-600,000 years ago. Both species have adaptations best suited for their habitat but, as DeSantis points out, there have been examples of hybrids that have been better able to adapt to a particular environment, “particularly if that environment is deviating from what it once was.” So, it is yet to be seen whether the pizzly population will actually increase in size.

The famous grizzly–polar bear hybrid on display at Ulukhaktok airport in Canada’s Northwest territories. This animal is 3/4 grizzly and 1/4 polar bear. Photo: Samuell

But since the Arctic is currently warming at an unprecedented rate, and the Arctic sea ice is disappearing, we are rather positive that we are going to see more and more of these animals in the years to come.


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