Biology Reference
In-Depth Information
and weighs from 24 to 50 percent more; the red weighs in at seven to eight ounces or more, while the
northern flying squirrel only tips the scales at a distinctly lightweight four to six ounces.
The little southern flying squirrel is considerably smaller than its more northerly cousin. In fact,
it's the smallest of all our North American tree squirrels. With a total length of about eight to nine
inches—three to four and a half inches of it being tail—this diminutive glider weighs only two to two
and a half ounces. By way of comparison, this is about half of the northern flying squirrel's weight, and
only one-third of the red squirrel's.
Even our northern flying squirrel is small, however, when compared to some of the giant Asian fly-
ing squirrels. One, the red giant flying squirrel
(Petaurista petaurista)
of Southeast Asia, has a com-
bined head and body length of about sixteen inches, plus a tail slightly longer than that—a total length
approaching three feet! So large is this squirrel that its thick pelt of mahogany-red hair is occasionally
a commercial item. This squirrel can reputedly glide for very long distances, but
Walker's Mammals of
the World,
a highly respected source, only lists a known glide distance of about 225 feet.
Although the ranges of our two native flying squirrels show considerable overlap, their habits and
habitat requirements vary considerably. The northern flying squirrel, as its name implies, inhabits much
of Canada and Alaska. It also spills down into the United States through New England and New York
and all the way along the spine of the Appalachians into Tennessee and a bit of western North Caro-
lina; into the northern portions of the Great Lakes states; southward through the Rocky Mountains; and
down the Pacific coast into a considerable piece of California.
In contrast, the southern flying squirrel is found in much of New England and nearly all the rest of
the eastern United States as far west as the edge of the Great Plains. These ranges alone are a clue to the
different habitat and food requirements of the two species. In the far north, where much of the northern
flying squirrel's habitat lies, forests are almost exclusively coniferous. Conversely, throughout much of
the southern flying squirrel's range, deciduous forests are very much the rule. Where their territories
overlap, forests contain areas of conifers, mixed growth, and deciduous stands.
These differences in habitat have considerable implications as far as food is concerned. In much
of the northern flying squirrel's range, nut trees are absent. Although this squirrel devours nuts avidly
when they're available, it can make do without them. In summer, lichens and fungi make up much of
its diet; in winter, the northern flying squirrel is known to raid the caches of red squirrels. In the latter
instance, it seems doubtful that the red even realizes it's being robbed, since it is sound asleep when the
nocturnal robber pillages its hoard of cones. Arboreal lichens are also an important winter food source.
Berries, seeds, and fruit are also prominent in the northern flying squirrel's diet. Although we don't
think of flying squirrels as carnivorous, like red and gray squirrels (see chapter 3) they eat meat
whenever it's available. Mostly, their meat supply consists of nestling birds (they consume the eggs, as
well) and the young of mice, voles, and shrews.
Not unexpectedly, southern flying squirrels are more dependent on nuts, but they eat many of the
same foods—fungi, seeds, fruit, and berries. They also consume a substantial amount of meat. In fact,
the gentle appearance of this tiny glider is quite deceptive, and a number of experts regard it as the most
