New bear hybrids emerging as climate shifts territories

Extremely rare species of bears are emerging in nature. We are talking about hybrid bears known as growler and pizzly bears, which are crossbreeds of polar and grizzly bears. Although they are currently few, scientists predict their population will increase.

Scientists regularly report the discovery of entirely new animal species previously unknown to science. One of the most recent discoveries was identifying the snake Rhynchocalamus hejazicus in Saudi Arabia. Now, researchers from Polar Bears International have published findings in the journal "Conservation Genetics Resources" about these new bear hybrids.

These hybrids, growlers, and pizzly bears are rare because they usually interbreed in zoos. They can also encounter each other in the wild, which is relatively uncommon. Nonetheless, both species are increasingly shifting their territories, raising the chances of crossbreeding in natural habitats.

Scientists examined several hundred wild polar and grizzly bears to understand how many hybrids develop. They found that growler and pizzly bears are likely to increase in number due to climate change. The environment significantly shifts their territories, leading to more frequent encounters and crossbreeding between polar and grizzly bears.

The difference between the two hybrids lies in the parentage. Scientists explain that a growler is the offspring of a male grizzly bear and a female polar bear, while a pizzly is the offspring of a male polar bear and a female grizzly bear.

– The overlap typically happens in the summer when polar bears are on the mainland coast waiting for the sea ice to form again – explains Dr. Ruth Rivkin from Polar Bears International.

Scientists acknowledge that crossbreeding between the two species in the wild is currently extremely rare. However, they predict that growler and pizzly hybrids will become more common. To better study these hybrids, they have developed a genetic sequencing chip to analyze samples from polar and grizzly bears accurately.

Thanks to this new chip, among the 371 samples collected from polar bears and 440 from grizzly bears, scientists identified only 8 growler hybrids. If global average temperatures continue to rise, scientists expect an increase in the number of bear hybrids in the environment.