Gray squirrels typically are gray on the top of the body and have a white underside. The gray squirrel measures 18 to 20 inches long, its broad bushy tail accounting for about half its length, and weighs 1 to 1.5 pounds. Most adult gray squirrels first breed in mid-December or early January, and 5 to 10 percent of older females may breed again in June. The gestation period is 42 to 45 days, after which gray squirrels typically give birth to three young. The young are born hairless and blind and spend their first 10 to 12 weeks in the nest before beginning to explore the outside world. Gray squirrels typically live about two to three years.

Fox squirrels are gray to reddish-gray above and buff to pale orange-brown on the underside. The fox squirrel is so named because its color often resembles the brownish red-orange of the red fox. Larger than gray squirrels, fox squirrels are about 21 inches long and weigh nearly 2 pounds. Fox squirrels mate in January and give birth to two to
four young in late February or early March. Unlike gray squirrels, fox squirrels have only one litter per year.

Flying squirrels  The flying squirrel is about 8.5 inches long, including a 3.5 inch tail. Its large, round eyes are adapted for night vision. The fur of the flying squirrel is soft grayish-brown above and white on the underside. The flying membrane is a loose flap of skin between the front and hind legs on either side of the body. The membrane is stretched tight when the legs are extended, allowing the squirrel to soar or glide but not to fly in the true sense of the word. The broad, flat tail is used as a rudder to guide the animal while it is soaring. Flying squirrels can sail up to 40 yards in a downward direction, often soaring from tree to tree. Two to six young are born in April or May following a 40-day gestation period.

Squirrels can become a nuisance when their feeding and nesting habits conflict with human interests. Damage frequently occurs when squirrels feed on cherry blossoms and ripe pears or chew the bark of fruit trees. In addition, squirrels may carry off mature nuts. In gardens, squirrels may eat planted seeds, flower bulbs, mature fruits such as tomatoes, or grains such as corn. Hungry squirrels also frequently raid bird feeders. In residential areas, squirrels sometimes travel on power lines and may short out transformers. Tree squirrels can become a problem when they gnaw on wires, enter buildings, and build nests in attics. Squirrels may damage siding, insulation, or household contents when they take up residence in homes or other buildings