Biology Reference
In-Depth Information
at a friend's house, just as a barred owl hooted close by. “That's a bear,” said his host excitedly. When
the ornithologist demurred and identified the hooter as a barred owl, the host flatly refused to believe
him!
Charlie Willey also told me an amusing and instructive anecdote concerning a college student from
Vermont who was Charlie's assistant one summer. In the course of their work with bears, Charlie men-
tioned that bears don't hoot. The young man, who had been raised on this fiction, was somewhat skep-
tical at first, but finally appeared convinced that Charlie was right. Then he went home for the weekend
and returned on Monday to tell Charlie with great excitement that bears really
do
hoot. It seems that he
had gone into the woods with an old hunter and woodsman, and at some point they had heard a bear
hoot.
“But how do you know it was a bear?” Charlie asked him.
“Because he told me so,” responded his assistant. This reply was remarkably similar to that of
Josephine in Gilbert and Sullivan's HMS Pinafore: “But I know Sir Joseph is a good and great
man—for he told me so himself.”
Like the brown and polar bears, black bears have delayed implantation of the embryo. Although mat-
ing occurs in the summer, the fertile eggs don't implant and begin to develop inside the female until
late fall. This is an evolutionary adaptation that makes great sense. In years when food is very scarce
before hibernation, cubs might sap the mother's strength so that both mother and cubs would perish.
Under this regimen, the embryos simply don't implant if the female hasn't fattened sufficiently for hi-
bernation, thus ensuring her survival to breed another year.
As the rich foods of late summer and early autumn mature, bears accelerate the pace of their feeding
in a race to accumulate sufficient fat to see them through the winter. Now, in addition to the usual plant
foods, insects, and small rodents, the bruins eagerly seek foods such as acorns, beechnuts, apples, and
corn. At this season of the year they can be especially destructive to farmers and orchardists. For that
reason, bear hunting seasons often open in time to reduce or eliminate some of the damage caused by
bears, especially sows with yearling cubs. As one biologist explained it, “A family of bears in a farm-
er's cornfield makes it look as if someone had driven a Mack truck around and around in the corn.”
As winter draws near, black bears seek a den for hibernation. Although bears are commonly thought
to dwell in caves and hibernate there, they don't need or use shelter during the warm months, and there
are far too few caves to meet the bears' winter needs. Most black bears in northern regions hibernate
beneath the roots of a blown-down tree, in a hollow in the ground, in a huge hollow tree, in a fox or
coyote den that they've enlarged, or in some similarly sheltered place. In areas where summer cottages
are abundant, such as parts of New York's Catskill Mountains, bears often den beneath porches or in
crawl spaces under the uninhabited buildings. The human occupants leave well before the bears den
in late autumn, and the bears depart in the spring before the humans return. It's a fine situation for the
bears.
Where cold isn't extreme, black bears even build huge nests for winter quarters. These are nothing
like the so-called “bears' nests” in beech trees; instead, they're constructed on the ground—great, dish-
