Hybrid bears on the rise: Climate change drives growler, pizzly growth
Scarce species of bears are appearing in nature. This refers to the so-called growler and pizzly bears, hybrids of polar and grizzly bears. Although there are currently very few of them, scientists point out that their numbers will increase.
Scientists constantly report the identification of entirely new, previously unknown species of animals. One of the most recent discoveries of this kind was the finding of the Rhynchocalamus hejazicus snake in Saudi Arabia. However, researchers from Polar Bears International are writing in the journal "Conservation Genetics Resources" about new species of bears.
These are hybrids of polar bears and grizzlies. The resulting growler and pizzly bears are scarce specimens, as they primarily interbreed in zoological gardens. They can also meet in the wild, which is generally uncommon. Nonetheless, both species are increasingly expanding their territories, thus increasing the chance of these species interbreeding in their natural habitat.
Polar bear and grizzly hybrids
Researchers studied several hundred wild polar bears and grizzlies to determine how both species' hybrids are developing in nature. They found that the number of growler and pizzly bears will increase due to climate change. The environment, in turn, affects the aforementioned shifting of their territories. This way, polar bears will increasingly meet and interbreed with grizzlies in the wild.
The difference between the two hybrids comes from the origin of the offspring. Scientists explain that a growler is the offspring of a male grizzly bear and a female polar bear. On the other hand, 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 know that interbreeding of both species in natural conditions is extremely rare. However, they predict that despite this, grizzly and polar bear hybrids will become more common in the future. Therefore, they decided to develop a chip for genetic sequencing, allowing them to study polar bear and grizzly samples in more detail.
Thanks to the chip mentioned above, among the 371 samples collected from polar bears and 440 from grizzly bears, researchers identified only 8 growler hybrids. However, if average annual temperatures globally continue to rise, scientists expect an increase in the number of bear hybrids in the environment.
