Endangered polar bears are multiplying with grizzly bears, bringing about hybrid "pizzly" bears, and it's being instigated by climate change. As the world warms and Arctic sea ice becomes thinner, polar bears that lack food relocate to further south, where they unite with grizzlies, whose ranges are expanding northwards.
And with that growing association between the two species more mating occurs, and therefore boosted sightings of their hybrid generation.
Grolars
With characteristics that could give them an advantage in warming northern habitats, some researchers make guesses that the pizzlies, also called "grolars", could be going nowhere. A paleontologist and associate professor of biological sciences at Vanderbilt University in Tennessee, Larisa DeSantis, said to Live Science: "Commonly hybrids are not better convenient to their environments than their parents, but there is a chance that these hybrids might be capable of foraging for an extensive range of food sources."
DeSantis said polar bears possess longer skulls, which makes them good at taking seals out of the sea. But their molars are quite smaller than normal for the size of their body because all they feed on is blubber all day. Grizzlies, on the other hand, can feed on whatever they like. Researchers are not yet sure, but maybe the mid skull of the pizzly could confer a biomechanical usefulness."
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The Rare Animal
Polar bears and grizzly bears only disunited 500,000 to 600,000 years ago, so the two species can mate and give birth to offspring that are viable. Research made in captivity and a study carried out in the wild also gave a suggestion that the hybrids are very fertile and have themselves produced young.
In 2006, wild viewing of hybrid pizzly bears started, when a hunter shot at what he was thinking was a polar bear in the Northwest Territories of the Canadian Arctic. When he took a clearer look he discovered an altogether more uncommon animal: A bear possessing a cream-white fur of a polar bear but the humped back, long claws, hallow face, and brown patches of a grizzly bear.
Rise of the Pizzlies and Decline of Polar Bears
DNA tests clarified that the animal was a hybrid - the first recorded wild offspring of a grizzly bear and a polar bear. Since then, the viewing of the hybrids has been increasing in number, with a 2017 study in the journal Arctic exhibiting eight hybrids coming from a single female polar bear who copulated with two grizzly bears.
The rise of the pizzlies happened at the same time as polar bears' decrease: their numbers are predicted to decline by over 30% in the next 30 years, as stated by a 2016 study in the journal Biology Letters.
This overhasty fall is connected partly to grizzly bears encroachment into polar bear ranges, where they defeat them for substitute food sources, but also to highly specialized diets of polar bears, as DeSantis focuses in research released on April 1 in the journal Global Change Biology.
Related Article: Pizzly or Grolar Bear? The Hybrid Grizzly and Polar Bear is the Cutest Result of Climate Change
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