Wall Street Journal: Until recently there were only two species of flying squirrels in North America. But the Northern and Southern species have been getting cozy and are interbreeding. WSJ's Angus Loten reports.
What happens when a Southern flying squirrel meets a Northern flying squirrel, and the mood is just right?
A decade ago, the answer would have been nothing. But more recently, Canadian wildlife researchers collected DNA evidence showing the two species can and do interbreed, as the Southern flier's habitat...