Polar bear and grizzly bear hybrids, known as 'pizzly bears,' could become more common because of the climate crisis
- When polar bears and grizzly bears mate, the hybrid is called a pizzly bear, or a grolar bear.
- Pizzlies are becoming more common in the Arctic and the climate crisis is likely playing a role.
- As grizzly bears move further north with warmer temperatures, they're more likely to meet polar bears.
Pizzly bears, sometimes called grolar bears, are a bear hybrid that could become more common in the Arctic as a result of the climate crisis.
The pizzly bear is the result of polar bears and grizzly bears breeding, according to Larisa DeSantis, a biology professor at Vanderbilt University.
"We've known about pizzlies for quite some time, but their occurrence may be more common with ongoing Arctic warming," DeSantis said.
A pizzly was first discovered in the wild in 2006, when a hunter in Canada's far north killed a bear with white fur and brown patches as well as the humped back and long claws characteristic of a grizzly bear. DNA testing confirmed the bear was a hybrid, The Associated Press reported at the time.
Since then, sightings of pizzlies in the wild have become more common. A 2017 study published in the journal Arctic documented eight pizzlies who were the offspring of one female polar bear that had mated with two separate grizzly bears.
According to DeSantis, grizzly bears are moving further north as temperatures rise. Meanwhile, "polar bears are increasingly having to search for other food sources, when hunting seals from sea ice become untenable," she said.
Polar bears typically rely on sea ice to hunt for seals, which make up the vast majority of their diet. A 2018 study published in Science found as sea ice continues to decline, "polar bears are likely to experience increasingly stressful conditions and higher mortality rates." And arctic sea ice is declining rapidly, as the Arctic experiences higher rates of warming than the rest of the globe, according to the National Oceanic and Atmospheric Administration.
DeSantis said polar bears and grizzly bears have been observed near whale carcasses, prompting them to "engage in opportunistic mating." Since polar bears and grizzlies only diverged about 500,000 to 600,000 years ago, she said, their offspring are able to produce offspring as well.
But it will take time and additional research to know how well suited these hybrids are to survival.
"Most of the time, hybrids are not more vigorous than either of the two species," DeSantis said, adding that individual species generally have adaptations best suited for their habitat. But she said there have been some instances where hybrids are more vigorous, "particularly if that environment is deviating from what it once was."
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