Both squirrels grow to a length of about 8 inches, and can weigh about half a pound. Northern Flying Squirrel Facts . Northern flying squirrels (Glaucomys sabrinus) and southern flying squirrels (Glaucomys volans) are the only two native flying squirrel species found in North America.They are both gray-brown, but the northern flying squirrel has belly fur that is gray at the base, and for the southern flying squirrel the belly fur is all white. Northern flying squirrels are brown or gray in color and have off-white fur on their bellies. Both are similar in color, but the southern flying squirrel is the smaller of the two. Legal acquisition of a pet Northern flying squirrel is typically obtained through a breeder and then by securing the proper state permits (this varies by state). While there are 44 species of flying squirrels, just two of these species (Northern and Southern flying squirrels) are native to North America. The squirrels are nocturnal. The general color of the upper portions of the body, head and tail of the southern flying squirrel is drab olive gray, darkest and almost black at the edges of the membranes. But even the northern flying squirrel is smaller than a red squirrel. Genus: Glaucomys Volans Southern Flying Squirrel (meaning grey mouse, flying) There are two species of the flying squirrel found in North America, the Northern Flying Squirrel and the Southern Flying Squirrel. The southern flying squirrel is about the size of, yes, a chipmunk (which is a ground squirrel). The animal has a long, flat tail and large round eyes for enhanced night vision. “The northern flying squirrel [at three to five ounces] may be half again or may be twice as big as the southern,” he said. Description. The underparts of the body and head are white to creamy white, the hairs showing no gray at the bases (as they do in the northern flying squirrel, G. sabrinus). The northern flying squirrel is a bit larger and darker in color than the southern variety. The northern flying squirrel is a small animal, about 10 inches long.