Polar Bears: The Brown Bear’s north Sisters

Scientists estimate that polar bears diverged from brown bears in between 250,000 and 130,000 year ago—a recent break-up when it concerns evolutionary history. Lasting hereditary similarities make the two bears organic sister species, more closely pertained to one another than to any type of others.

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Aside indigenous their hair colors, the similarities are obvious. Both bear are an effective predators, with male polar bears farming as large as 1,500 pounds, the very same size as the world’s biggest brown be affected by each other subspecies, the Kodiak bear.

But Ursus maritimus has also evolved to complement its polar environment, growing a much longer snout than brown bears’ and larger, paddle-like paws, both of which help polar bears in hunting seals. This specialization has now made the polar bear an ext vulnerable than its more widespread, adaptable brown be afflicted with relative. As sea level climb threatens the polar bear’s Arctic habitat, things will change for grizzlies, too.

Climate Confusion

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As climate adjust melts Arctic sea ice, polar bears choose this one in Churchill, Manitoba, are progressively ranging inland onto historic grizzly be affected by each other habitat. (Photo by R. Pilkington)

Climate adjust is melt the polar bear’s homeland—the year-round ice of the Arctic Ocean—at an amazing rate. As their seal-hunting grounds turn to open water, the north bears room struggling to adapt. Many are spending an ext time inland, and also farther south. In ~ the exact same time, warmer temperatures are opening new habitat to grizzlies, together the borders of plant growth and corresponding pet communities customs northward.

The result of this parallel trends? The old sisters—polar bears and also brown bears—are cross paths much more often. And the outcomes are fascinating.

A study released in 2015 in the Journal the Mammalogy by Susanne Miller, James Wilder and Ryan Wilson tracked interactions between the two types during the lengthening fall open-water period along the coastline of the Beaufort Sea in Alaska. As hungry polar bear ranged inland come scavenge whale remains near villages, new competitions emerged. The researchers discovered it more common for members that the same species to fight end food, but also recorded previously-undocumented competitions in between polar bears and also brown bears, throughout which the grizzlies, like usual older siblings, asserted social dominance.

When the two species meet, castle don’t always fight, however. Another phenomenon intensified by climate adjust is a increase in recorded polar bear-grizzly mating. What to call these hybrids? Scientists and reporters have used the mix names “grolar” and “pizzly,” while part have argued combining the bears’ Inupiaq names—nanuk (polar bear) and analak (grizzly)—and dubbing the crossbreeds “nanulak.” everything the name, the outcomes are visually arresting and carry out for a lively debate.

Room to Roam

What go the changing Arctic landscape median for brown bear farther south? when recovering grizzly populations in the northern Rockies won’t be seeing polar bear on your doorsteps at any time soon, we deserve to learn from the great of the north. Grizzlies will range into brand-new habitat as soon as it opens to them, whether it’s newly-exposed coast in the Arctic or stream corridors ~ above Montana’s Rocky hill Front. And also from polar bears to exclusive ranches, they will carry out so without heed because that what may be waiting for them.

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That’s why grizzlies require habitat protection and also conflict prevention as they continue to recover and also expand their range. If their northern sisters face an uncertain and vulnerable future, we can work to make sure the an excellent Bear the the reduced 48 has room come roam because that generations to come. See just how you can aid today.