Apart from these differences, and larger size, the northern flying squirrel resembles the southern. Adults are 250-298 mm (10-11.7 in) in total length, and weigh 75-125 g (2.6-4.4 oz). The range is ...

There are about 50 species of flying squirrels ranging across most of North America down into Central America, and stretching from Southeast and Northern Asia into Siberia and Scandinavia.

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.

With built-in parachutes in the form of wing-like flaps of skin stretching from leg to leg, West Virginia northern flying squirrels glide among the trees in the mountains of Appalachia. Flying ...