Our scintillating squirrels
New nature column explores lives of local rodents
By Callan Bentley
Flat Hat Variety Editor
It has become almost routine on campus. You are walking to class or perhaps to the post office, and you hear a frantic rustling noise emanating from a trashcan. You stop and peer into the barrel and are surprised to see the garbage suddenly sprout a bushy gray tail. Suddenly, a squirrel pops his head out and seeing that you are watching him, jumps to the ground and sprints for the nearest tree. You shrug and continue on your way. It may have just been a squirrel in a trashcan, but you have just witnessed a moment in the life of an amazing animal.
The eastern gray squirrel
(Sciurus carolinensis, to biologists) is a small mammal. As an adult,
it may reach a length of 20 inches and weight about a pound. The squirrel has
light gray fur, white underparts, short yellowish hair on its face and muzzle,
and long black whiskers. Four large incisors, which the squirrel uses to cut
its food, are its most prominent teeth. The ears of the eastern gray squirrel
are small, triangular, and usually erect.
The male and female are generally
of equal size, weight, strength, and activity. They have hand-like forepaws,
each with four long functional digits, and the fifth digit acting as a sort
of impromptu thumb.
The most striking aspect
of this arboreal rodent is its tail. All North American squirrels seem to have
large tails, but our local S. carolinensis is deemed to have the largest and
most conspicuous. In fact, half of the animal's length is taken up by "the
most lavish and magnificent tail of any furry quadruped," according to
Eugene Kinkead in his comprehensive volume The Squirrel Book.
The gaudiness of the squirrel's tail is a bit of a mystery. For some time, mammalogists have puzzled over why the animal evolved such a large appendage. One indication of the tail's importance is the amount of time that the owner spends grooming and fluffing it. It is possible that the squirrel uses it as an ornament for attracting mates. Also squirrels have been observed using their tails as makeshift umbrellas, holding them over their heads during rain or hail. It is likely that the tail also serves as an aid to balance as the squirrel cavorts high in the treetops.
Apparently, the tail also
functions to slow a squirrel's fall if it misses a branch. Kinkead relates an
interesting story about this ability. A traveler in Mexico had seen two young
boys capture a large squirrel that they believed to be bewitched and placed
it in a pillowcase. Kinkead continues:
"They took this to the
edge of a crag overlooking the valley of a river whose floor was 600 feet below.
On the crag the pillowcase was opened. The squirrel had the option of remaining
in it or leaping out in to the air above the valley. It chose the latter. It
leapt….It fluttered rather than fell into the abyss below. The legs began
to move like those of a swimming poodle dog, but quicker and quicker, while
the tail, slightly elevated, spread out like a feather fan."
The squirrel landed on a
rock ledge, squatted on its hind legs, and smoothed its ruffled fur. Then, none
the worse for wear, the animal hopped off the ledge and down to the river.
One naturalist has gone so
far as to suggest the squirrel can survive any fall, which in the light of the
above story, is not entirely implausible. Often after a fall the rodent will
lie stunned for a while, but will get up later to walk off as if nothing out
of the ordinary had occurred.
The eyes of the eastern gray
squirrel are another extraordinary aspect of its anatomy. Squirrels can see
a great distance, perhaps farther than any other rodent. It has been proposed
that this ability evolved because of this particular rodent species' arboreal
habits. Interestingly enough though, their short-range vision is rather poor.
I have seen squirrels run down trees to a peanut I have tossed to them, only
to lose sight of it once they reach the ground.
The squirrel has a varied
diet, and seasonal differences are obvious. It is an omnivore, and has been
known to consume twigs, bark, seeds, buds, catkins, flowers, berries, hazelnuts,
mushrooms, bird eggs, insects and insect larvae.
Some squirrels have shown
a fondness for candy. In Pittsburgh's Shenley Park, one squirrel has discovered
the world of vending machines. Reaching a paw into the machine, it was able
to pull out candy bars in the lowest row. He preferred, as one might expect,
candy bars with nuts. Almond Joy over Mounds, any day of the week.
Another story tells of a
woman who set out a box of brandy-filled candies in her guest room. An unexpected
guest arrived in the form of a gray squirrel, who ravaged the sweets. When the
woman returned, all the candy was gone, and the little mammal was lounging on
the bed, quite intoxicated and making a humanlike laughing sound.
Food is plentiful in the
summer, but winter presents a stark absence of nutrients for squirrels. The
eastern gray squirrel prepares for the food shortage by hoarding edibles. It
is often seen burying nuts so that it may dig them up in wintertime. The squirrel
has a fantastic sense of smell, and can detect buried acorns under several inches
of snow. Some of the nuts are invariably missed, however, and will sprout leaves
and roots. Given enough time, they will grow into trees. In this way, the animal
helps to replenish its food supply by replanting the forest.
The eastern gray feeds most
in the early morning and late evening, but it never passes up fodder of opportunity,
should something yummy present itself off that schedule. This is a lucky thing
for us humans, because it affords us an opportunity to draw squirrels closer
to us by tantalizing them with some food. Peanuts are popular, but rather unhealthy
for the squirrels. Dr. Richard van Gelder, a mammalogists with the American
Museum of Natural History in New York, suspects that some fur loss and poor
eyesight among urban squirrels may be caused by over-consumption of peanuts.
The eastern gray squirrel
is diurnal, meaning that it forages only in the day. It wakes at dawn and beds
at dusk, and may occasionally (during full moons) forage at night, but such
expeditions are fraught with danger, as this is the time that squirrel-sampling
owls are on their evening hunt.
The call of the eastern gray
is described as a chattery "qua-qua-qua-qua-a-a," repeated over and
over. The College Woods offer an excellent opportunity for amateur naturalists
to observe squirrels. The animals are a common sight in an hour's worth of hiking,
and will ignore an observer's presence as they quest for food. The same could
be said of the garbage cans on campus.
If you decide to go squirrel-watching,
also keep your eyes peeled for the homes of these perky mammals. Often, they
will live in holes in trees. A pair of squirrels live just above Crim Dell in
such a cavernous maple, but it is a more frequent sight to spot large nests
high in the canopy. These nests are built in the crooks of tree branches and
are constructed of twigs, leaves, bark, grass, and stray pieces of fibrous litter.
The round conglomerations will be especially visible in winter months, when
their bulky silhouettes will be the only decoration on the campus' otherwise
naked deciduous tree limbs.
Also of interest are young squirrels. Most squirrels are delivered in February and August, so now is prime time to find young "pups" learning to eat.
If you are lucky in your observations, you will be able to watch some fantastic
and bizarre activity. Squirrels are extremely playful, as anyone who has watched
them chasing each other around a tree could tell you. They also sometimes display
amazing acrobatics. Robert E. Wrigley, naturalist author of Mammals in North
America, tells of such an incident: "I once saw a gray squirrel performing
a most amazing routine. It repeatedly ran up the base of a tree and then back-flipped
to the ground."
I witnessed a similar display
earlier this semester. A gray squirrel ran up to a chair sitting next to my
dorm and hurdled the metal bar that connected the chair's legs. It spun around,
hurdled again in the opposite direction, and so on, again and again. Then, it
grasped the bar with its forepaws and spun around three or four times. It must
have been dizzy after this exercise, because it stopped and rested for a few
minutes. Then, evidentially having regained its equilibrium, it scurried back
to the chair and practiced its gymnastics for a few more minutes, until it was
scared off by a tourist.