Adult gray squirrels weigh 1 to 1½ pounds and are 18 to 20 inches in length; about half this length is a broad, bushy tail. Most grays are colored silvery-gray above and off-white below, often with rusty or brownish markings on the sides or tail. Albinism is rare, but melanism (black coloration) is fairly common. Once, black-phase gray squirrels were found throughout Pennsylvania; today they occur most often in the northcentral counties. “Black squirrels” may be any shade from dark gray to nearly jet black, often with a brownish tinge.
Gray squirrels eat mast, acorns, hickory nuts, walnuts and beechnuts. Other foods include berries, mushrooms, pine seeds and corn (only the germ at the base of the kernel is eaten), and dogwood, wild cherry and black gum fruits.
Grays are probably the wariest of Pennsylvania’s squirrels. They’re quicker than fox squirrels and less vocal than reds, although they sound warning barks and assorted “chucks.” Hawks, owls, foxes and tree-climbing snakes occasionally kill young squirrels, but adults are not easily taken. Predators do not appreciably affect squirrel populations on good ranges, availability of food is the key to population size.
A maximum life span for a wild gray squirrel could be 10 years or even longer, but few live more than two or three years. Grays live in nests and dens. They build leaf nests in trees near good food supplies in both summer and fall.