Squirrel species that inhabit the trail include: the gray squirrel, fox squirrel, red squirrel, northern flying squirrel and southern flying squirrel. Named for its color, the gray squirrel is gray, though in the northern states it looks black. Its tail has some silver hairs amongst its bushy gray. The fox squirrel is the largest of the tree squirrels and has a large bushy tail with yellow-tipped hairs.
In the north it is gray with a yellow underside, and in the south it is black, has a white blaze on its face, and has a white tipped tail. The smallest of the tree squirrels is the red squirrel. This squirrel lives from northern Virginia north. As the name suggests, it has a reddish coat but a white/gray underside. Its tail is also red, though it features a black band edged in white. The flying squirrel is nocturnal, and thus rarely seen by hikers.
Between the front and hind legs are loose folds of skin that when extended act as a wing, allowing the squirrel to glide. Even though it is the smallest, the flying squirrel eats insects and occassionally the flesh of other small animals in addition to the squirrel diet of nuts and seeds.