Last year I was teaching a lesson on food chains and one of the third graders hollered “SQUIRREL!” which stopped me mid-sentence.

We all stood perfectly still as we watched the squirrel scamper up a tree and out of sight. It was just a gray squirrel, but we all watched it as if it were something rare.

Most Pennsylvanians are familiar with gray squirrel, which is the most common squirrel; the fox, red and flying squirrels are three other species native to the state.

Gray squirrels are approximately 18 inches in length with the tail making up about seven inches and they weigh about a pound.

With rounded heads and ears, gray fur tinged with red, and white or cream-colored bellies. Their bushy tails have many uses such as balance, warmth, an umbrella, communication and as a rudder when swimming.

At the center, we have a taxidermy display of three squirrels and it’s interesting to hear what people have to say about the trio.

Unbeknown to them, all three are gray squirrels even though only one of them has gray fur.

To our north, the black-furred squirrels are more common than gray. It’s not uncommon for a litter of squirrels in the northern part of our state to have both gray and black squirrels in the same litter. Albinism also occurs as well. The variations occur in the fur color differences because of heredity, genetics, and habitats.

Where do they live?

Gray squirrels live throughout the eastern United States, ranging from southern Canada to Florida, and west into eastern Texas. This species has also been introduced to many locations outside of its native range including Washington and British Columbia.

Eastern gray squirrels are found in every county in Pennsylvania.

An assortment of mast - seeds, nuts, and berries such as acorns, hickory nuts, walnuts, beechnuts, pine seeds - they also feed on maple samaras, wild grapes, buds of maple, tulip popular, flowering dogwood, and black cherry.

If those choices become difficult to find they will also prey upon juvenile birds, bird eggs, and amphibians. At the end of the summer, gray squirrels will store seeds and nuts to feed on when food is scarce during the winter months.

They have been known to make hundreds of caches buried at the surface, with few more than ½ inch below the ground.

Locating buried nuts under a foot of snow isn’t a problem for them because they will tunnel under the snow in search of hidden food. Because of this keen sense of smell, about 90% of the nuts are found while the remainder may be found by other animals, or some may eventually germinate.

Gray squirrels live in mixed forests as well as in suburban and urban areas. The trees most commonly used by gray squirrels are white oak, red maple, and sweet gum. Using old woodpecker holes or natural tree cavities as dens is quite common. Of course, they also build large nests composed of leaves and twigs to both live in and raise young.

Gray squirrels are often social and will share their nests with other gray squirrels during certain times of the year.

The chase

Squirrels mate twice a year from December to February and from May to June.

A mating “chase” is often involved, with several males following a female as she moves about during the day.

Gray squirrels are polygamous, with one male mating with several females.

After mating, the females are pregnant for 45 days. Litters range from 2-6 young that are born hairless and helpless. Frequently, the spring litter of young is born in a tree cavity, while the second, late-summer or early fall litter is born in a leaf nest.

Females often move their litters back and forth between cavity dens and leaf nests, to escape predation or parasite infestation as well as weather changes. The young are weaned in about 50 days. Typically, gray squirrels have two litters per year. The second litter stays with the female over the winter.

I know the next time someone yells, “SQUIRREL!” I stop to watch it - even if it is “just” a squirrel.

Jeannie Carl is a naturalist at the Carbon County Environmental Education Center in Summit Hill. The center rehabilitates injured animals and educates the public on a variety of wildlife found in the area. For information on the Carbon County Environmental Center, visit www.carboneec.org.