John Serrao
Feb 02, 2009
SOURCE: Pocono Record
Squirrels are certainly not the most exciting animals in the woods. In fact, they're such common, everyday sights that most people take them for granted and don't even give them a second thought (unless one is emptying a "squirrel-proof" bird feeder, in which case its uncanny perseverance and inventiveness must be admired).
Recently, however, a discussion with the Pocono Record editorial page editor, Paula Heeschen, about squirrels led me to do a little research, with the conclusion that squirrels aren't so ordinary after all.
First of all, the Pocono region is inhabited by six kinds of squirrels: the gray squirrel (which also comes in a melanistic, or black, form, as well as a very rare albino variation); the smaller red squirrel of our coniferous forests; the abundant but strictly nocturnal southern flying squirrel and its rare cousin, the northern flying squirrel; the eastern chipmunk (a type of ground squirrel); and �" this one may surprise you �" the woodchuck, or groundhog. All members of the order Rodentia, squirrels are differentiated from other local rodents by their bushy tails.
The one species that's most familiar to humans, of course, and the subject of this column, is the eastern gray squirrel. Common in forests, residential areas, parks and even big cities, this is one of the most adaptable mammals in the country. As long as there are trees, there will be gray squirrels, and since they're among the very few daytime mammals in our region, they're seen by everyone, all year long.
During spring and summer, a large part of the gray squirrel's diet is composed of the buds, fruits and flowers of trees and shrubs, along with roots, fungi and insects. It's during this period that the species produces its two litters of babies �" one in April and the other in July or August, generally in a bulky nest of dead leaves lined with twigs, bark, moss and grass up in the fork of a tree. An empty woodpecker cavity or other hole may also be used, and these are the gray squirrel's preferred winter sleeping quarters.
In late summer and fall, the gray squirrel's entire personality changes as it gets ready for winter, and this is when most of its amazing behavioral traits come into play.
Classified as a "scatter-hoarder" as opposed to a "larder-hoarder" (such as a chipmunk or red squirrel, which stores all its food in a big pile or underground chamber), the gray squirrel gathers acorns and other nuts (beech, hickory, walnut and hazelnut) and hides them one by one in holes dug in the ground. During the winter, it uncovers the nuts (or those buried by other squirrels in the community) by using its acute sense of smell. After a heavy snowfall, however, a gray squirrel can still locate stored nuts throughout its territory by relying strictly on its superb memory, as proven through studies in the Princeton Institute Woods.
Princeton's researchers also came up with another uncanny aspect of the gray squirrel's behavioral repertoire �" the ability to distinguish various species of acorns. Species in the so-called "red oak group" (red, black and scarlet oaks in our area) produce acorns that require two years to mature and don't germinate until after they've passed their first winter. These acorns are very rich in lipids (fats that help animals survive energy-intensive episodes such as winter or migration) but also high in distasteful tannins. Acorns of the "white oak group," on the other hand (white oak and chestnut oak), mature in one year but germinate almost as soon as they hit the ground in autumn. These acorns have only 25 to 50 percent of the tannins of red oak, making them "sweeter," but also only 10 to 20 percent of the valuable lipids.
Although gray squirrels have the physiological capacity to detoxify much of this tannic acid, they still suffer if kept on a strict diet of red oak acorns. However, if they stored only white oak acorns, many of the acorns might germinate in the soil and become useless as food for winter. The solution: bury both types but destroy the white oak's ability to germinate by biting into it to remove its embryo!
Or, eat mostly white oak acorns in the fall and bury red oak acorns for later.
Or, eat just the top half of red oak acorns and discard the bottom half, where most of the noxious tannins are concentrated.
Apparently, all three tactics are practiced, showing that the gray squirrel is indeed a connoisseur and not so mundane, after all.
