Climate change fuels the emergence of hybrid ‘grolar’ bears

By Elías Thorsson - June 24, 2024
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A polar bear mother and cub are seen on an ice floe in the Hinlopen Strait near Svalbard. (Andreas Weith / CC BY-SA 4.0 via Wikimedia Commons)

As the Arctic warms due to climate change, the overlapping territories of polar bears and grizzly bears have led to rare instances of hybridization between the two species, resulting in the emergence of “grolar” bears, reports ExplorersWeb. As polar bears and grizzlies continue to navigate the shifting Arctic environment, these hybrids could become more prevalent, posing new questions for scientists and conservationists about the future of these iconic species.

A new study has confirmed the existence of at least eight of these hybrid bears, products of male grizzlies mating with female polar bears. This phenomenon, driven by the changing climate, highlights the broader impacts on wildlife behavior and interspecies interactions.

  • Researchers used genetic sequencing to analyze 371 polar bears and 440 grizzly bears from Canada, Alaska, and Greenland, identifying eight hybrid bears, all from a single female polar bear, indicating a limited but notable occurrence of crossbreeding.
  • Melting Arctic ice and rising temperatures are pushing grizzlies into northern polar bear territories. This overlap mostly happens in summer, when polar bears are on land waiting for the sea ice to form, increasing the chances of interspecies encounters.
  • Grolar bears, hybrids from male grizzlies and female polar bears, occasionally form in the wild, while pizzlies, hybrids from male polar bears and female grizzlies, are rare and mostly seen in captivity. Female grizzlies rarely venture onto sea ice, reducing their mating opportunities with male polar bears.
  • With continued climate change, the number of hybrid bears may rise. Indigenous reports and scientific observations suggest that these hybrids could become more common, prompting further study on their ecological impact and the future of Arctic wildlife.