In the last few years, you may have heard about the hybrid between the polar bear and the grizzly—the "grolar." Or about narlugas, the offspring of narwhales and beluga whales. These species are a result of otherwise separate habitats shrinking together due to a warming climate. And many experts believe they are the first indications of a growing trend.
Take the bears, for instance. According to a recent study published in the journal PLUS Genetics, polar bears and brown bears are cross-breeding more now than ever before. Furthermore, hybridization is happening at an accelerated clip as melting ice drives polar bears on shore. The resulting bears have unique coloring, including muddy-looking snouts, dark stripes down their backs and the big heads and humped backs of brown bears.
Another study in Nature listed 34 potential and actual climate-change-induced hybridizations of Arctic and near-Arctic marine mammals. These include bowhead-right whales, spotted by members of the National Oceanic and Atmospheric Administration’s National Marine Mammal Laboratory 2009, and Harbor-Dall porpoises off the coast of British Columbia.
While many hybrid species are infertile, some of the new cross-breeds have successfully procreated. Recently, scientists discovered the cub of a female grolar and male grizzly bear.
The development is concerning for many researchers, who worry that hybridization could be disastrous for some species—especially those that are rare or endangered. As they mate with more common animals that are better-adapted for a warmer climate, the hybrid offspring could thrive while the endangered species disappear.