Polar bears and brown bears continued to mate with each other long after the species separated

Polar bears and brown bears were still mating with each other long after they had split into two distinct species, a new study has found. The two species are known to have separated up to 1.6 million years ago, yet new genomic evidence suggests they have inherited traits from each other much more recently. Scientists from the USA, Mexico and Finland analysed the genomes of 64 modern polar and brown bears, as well as that of an ancient polar bear that lived up to 130,000 years ago. While evidence of evidence of hybridisation was found in both brown and polar bear genomes, the latter carried a particularly strong signature of DNA from brown bears. As global warming continued to melt Arctic sea ice, the two bear species may run into each other more frequently, their shared evolutionary history could become more significant.