Biology Reference
In-Depth Information
Considering that a bat's echolocation can detect the tiniest gnat or distinguish a hard-shelled beetle
from a far more succulent moth, it's absurd to think that it would fly into someone's hair and entangle
itself there. In fact, that's the last thing that would occur to a bat, which infinitely prefers evasion
to entanglement! Perhaps this widely held myth originated with the fact that bats frequently swoop
close to people's heads. However, these bats are merely homing in on insects that are attracted by
their
prey—us. The bats know precisely where they are and what they're doing, and they have not the slight-
est intention of lodging in our hair.
It's the combination of great maneuverability and astonishingly accurate, sensitive echolocation that
makes bats in flight so fascinating to watch. Trying to capture the flight of a bat is nearly as difficult as
trying to capture the pattern of a swift-flowing stream. Before the eye can register and the brain com-
prehend the movement, it has already changed like quicksilver. Swerving, darting, swooping, diving,
changing directions almost at right angles without warning, a bat's flight is as unpredictable and inde-
cipherable as the movements of a prestidigitator's hands. Small wonder, then, that careful observation
of bats in flight is such a rewarding pastime.
In addition to older and more superstitious fears, bats are also feared because they're often portrayed
as a major threat of rabies to humans. This, unfortunately, is an enormous exaggeration.
Like most other mammals, bats can and do contract rabies and can transmit it to humans. Nearly
always fatal, rabies is a virus disease of the mammalian nervous system. In virtually all cases, rabies is
transmitted by a bite from a rabid animal in the last stages of the disease.
Rabid animals in the final stages of the disease exhibit one of two kinds of behavior. In the “dumb”
phase of the disease, a rabid animal acts extremely lethargic and may stagger and lose control of its
movements. In the so-called “furious” phase, the rabid animal often attacks anything around it, biting
living creatures and inanimate objects quite indiscriminately. Animals in this furious phase may also
foam at the mouth. This is the behavior that most people think of in connection with a “mad dog.”
At one time it was believed that bats harbored the virus without dying from it. Now scientists have
learned that rabid bats do indeed die from the disease. They don't, however, exhibit the furious phase of
the disease and usually don't attack other creatures. For this reason, anyone who avoids close contact
with bats—especially handling them—stands virtually no chance of contracting rabies from them.
Before considering what reasonable precautions one should take to avoid bat rabies, we should first
put into perspective what some regard as a great menace. From 1980 to 1996, a total of thirty-six cases
of human rabies were diagnosed in the United States. Of these, twenty-one were attributed to bats. This
amounts to about 1.3 cases per year of bat-caused human rabies in the United States.
By way of comparison, attacks by non rabid domestic dogs kill as many people in the United States
in one year as bat-caused rabies does in a
decade,
and ninety-five people died of bee stings in the Un-
ited States during the most recent year of reporting. Another way of viewing it is that rabies is now the
second-rarest disease in the United States and Canada, trailing only polio in that regard.
