Bats: everything you know is wrong
by Chris Klein
grew up with the same Halloween images and beliefs about
bats that most people have: blind, black, flying, hairless, rabies-carrying
rodents that could get tangled in your hair, if you weren't careful. Vampire
types might suck your blood while you were asleep. "Like a bat out
of hell," indeed. They seemed to be creepy pests with no redeeming
value, and I was glad there weren't any where I lived in Pacific Beach.
Just about everything I "knew" about bats
was wrong.
Of course, historically, I was in good company. Bats
have been looked on as symbols of evil, mystery and witchcraft centuries
before Shakespeare's witches' brew called for "eye of newt ... wool
of bat." The devil and dragons are often depicted with bat-like wings.
In some cultures, witch doctors wore bat amulets and made potions with parts
of bat bodies. In the middle ages, anyone who had bats, known as "witches'
birds," living in his house was accused of being a witch and burned
at the stake. In Central America, the bat was the god of death, and the
bat motif decorates burial urns and graves.
Admittedly, not all superstitions about the bat have
been evil. In China, bats symbolize good luck, long life and happiness.
Natives of eastern Australia regard the bat as man's lucky totem. In Anatolia,
a region of Turkey, some people still carry a bat bone for a love charm.
First century A.D. physicians in Egypt prescribed parts
of bats for curing asthma, rheumatism and baldness. In India, the skin of
large fruit-eating bats called flying foxes is still applied to cure lumbago
and rheumatism.
California Indians believed they could find the source
of a fire with the aid of bats. They also believed that the long-eared bat,
which has an arrow-shaped growth on its nose, ate volcanic rock and spewed
out fine arrows.
A Big brown bat, one of almost
1,000 species of bat. Bats are found worldwide on every continent except
Antarctica.
Batty about bugs
I got my first dose of reality one summer while rafting
down the Colorado River. At dusk, our camp by the river was surrounded by
dozens of bats, swooping, lurching and diving erratically. Thinking seriously
about zipping myself into the tent (they couldn't get into a tent, could
they?), I noticed that the river guides were completely ignoring bats passing
within inches of their bodies. I realized these lore-masters of the outdoors
probably knew something I didn't, and they were happy to fill me in.
The bats were after insects, their primary diet. This
included a sizeable quantity of mosquitoes. I've always been prime mosquito
bait. My opinion of the creatures started to improve.
An individual bat can eat up to 3,000 insects nightly,
and has been observed to consume from 600 to 1000 insects per hour. It is
estimated that the brown bat - common throughout North America - may eat
up to half its body weight in insects in a night's feeding. The 20 million
individuals of the freetail colony living in Bracken Cave in Texas may eat
a quarter million pounds of insects per night!
The seemingly erratic flight is due to the way the bats
catch the insects. As you may know, bats use a form of acoustic radar to
navigate. They send out ultrasonic squeaks, too high pitched for a human
to hear, and use the returning echo to determine the location, distance
and size of objects. When the echo indicates a bug-sized object, they home
in on it and use their wing to scoop it into their mouth. When the echo
indicates a larger object - say, a tree, telephone wire or my body - they
can avoid it, even on a pitch black night.
Nabbing an insect every 5 seconds or so calls for some
fancy flying, to say nothing of what using a wing to scoop up an insect
does to their flight plan.
So, given this degree of acoustic and aerobatic legerdemain,
was a bat really going to run into me or get tangled in my hair? No way.
Compared to their usual prey, I was a huge, slow moving object. Bats are
not at all aggressive (except to insects, of course), and evolution has
provided most mouse-sized creatures with the good sense to stay away from
large mammals. In short, I couldn't have come in contact with one if I had
tried.
I began to really appreciate their nightly insect vigil.
Every close sweep past my face was one less mosquito bite on my nose. Yes!
The California leaf-nosed bat,
so named for the small leaf-shaped pattern on the end of the nose, is one
variety found in San Diego County.
Myth-taken beliefs
Most of my other ideas about bats were wrong, too.
Rabies: Bats do not carry rabies more frequently than any other species,
such as dogs or cats (less than one-half of one percent of animals are affected).
Moreover, unlike dogs and cats afflicted with rabies, rabid bats rarely
show signs of aggression; they soon become paralyzed by the disease and
die. There have been no cases of large outbreaks of rabies among bats, as
there are from time to time among such wild animals as skunks and squirrels.
So, avoiding trouble is simple: don't pick up a sick
bat.
Rodents: Bats are not rodents, despite the fact that they bear a
surface resemblance to a winged mouse. Biologists tell us that bats are
more closely related to the order of primates (that includes humans) than
they are to the rodents. Their arm and hand bones are primate-like, and
they have canine teeth as opposed to the large incisors of rodents. This
is important to biologists; just thought you'd like to know.
Vampires: OK, so out of about 1,000 species of bat there are three
species of vampire bat living in South and Central America. In a painless
procedure, these bats draw small amounts of blood from sleeping livestock,
notably cattle and chickens. This reputedly does no damage to the cattle;
I'm not sure about the chickens.
The remaining 997 or so species around the world are
mainly insectivores or vegetarians, except for several species in India,
Southeast Asia, Australia and South America that feed on small birds, mammals,
or reptiles.
The vegetarian bats perform several valuable services
for the farmer. Nectar- and pollen-feeding bats are indispensable for the
reproductive success of many types of fruit trees. In tropical areas, some
of the fruits, nuts, spices and products derived from plants we have come
to depend on are pollinated by bats: avocados, balsa wood, bananas, sisal
for rope, cashews, cloves, dates, figs, mangos, peaches, agave for Tequila
and sugarcane for rum.
Appearance: While their wings are indeed hairless, the bats' bodies
are covered with fur. While many do have black or brown fur, others are
red, tan, white, yellow and even orange. Bats sport a wide variety of facial
features, some with leaf-like projections on their noses and fox-like faces.
The smallest bat species weighs only about 1/15 ounce and has a wingspan
of about 6 inches; the largest bat weighs about 2 pounds with a wingspan
of 67 inches.
Eyesight: Bats are not blind. In some species, particularly the herbivores,
vision is acute and necessary to survival.
Sounds: The squeaks and chirps that you hear bats make are used for
communication. As mentioned , their echolocation sounds are way outside
our range of hearing.
Bat and man forever?
Scientists are concerned that bats are waning in number
and in diversity of species. Sixteen of North America's 43 species of bat
are on the endangered species list, and eight more are under consideration.
It will take the efforts of individuals and groups dedicated
to bat education and conservation to prevent a drastic global decline in
the species diversity and overall population of these incredible flying
mammals.
For more information on bat roosting habitats,
conservation and new discoveries about bats, please write to: Environmental
Education Farm Foundation, 25344 County Road 95, Davis, CA 95616, or call
(916) 758-1387.
Bat Conservation International is an international membership
organization and information clearinghouse devoted exclusively to the promotion
of bat welfare and education about bats. Please write to them at: P.O. Box
162603, Austin, TX 78716-2603, or call (512) 327-9721.
Thanks to Barbara Moore and the Environmental Education Farm Foundation
for providing information for this article.
Barbara on bats
The following recollection was provided by Barbara Coffin Moore, naturalist,
author and Executive Director of the Chula Vista Nature Center.
've always been fascinated with bats. Just ask my mom!
One of the many things my mother remembers about my childhood was my habit
of bringing home bats in my pockets.
I went to a school with a real belfry (did you know
that belfry is British slang for head and "bats in the belfry"
means crazy?) and often the bats slept within reach of a curious eight-year
old. So it was just natural to pocket one of these small mammals and take
it home. Even though I had to take it back to school, a walk of 3 or 4 blocks,
I brought bats home over and over again.
Let's try to dispel some of the myths and invite these
wonderful creatures to co-exist with us, if not to share our lives.
Call to Action - What you can do
he San Diego Zoo has a display of some very large fruit-eating
bats near the elephants. Festival Drive in Oceanside, the La Paloma Theater
in Encinitas, and the old adobe at Gua-jome Regional Park are other places
to see bats.
Nearly all bats roost during the day and feed at night.
In areas near human habitation, bats may roost in buildings - in attics
of houses or other buildings, or under the eaves.
While I hope that you may now think more kindly about
bats, a colony of bats could still be a nuisance. If so, they can be simply
excluded by finding and sealing up roost entrances when they leave at night.
The best time to bat-proof a building is in September/October or March/April.
At other times, use caution to ensure that no baby bats or non-flying juveniles
are trapped inside. A light shined on their roosting spot will also discourage
them.
For bat control assistance, you can call San Diego Bat
Conservation at (619) 425-8987. They also give free lectures and talks to
schools, scout groups and other organizations.
On the other hand, you might now be so "batty"
that you'd like to have some around. Bat roosting tubes can be ordered fromthe
Environmental Education Farm Foundation; see the ad at the right. For information
on building a bat house, write to: Bat Conservation International, P.O.
Box 162603, Austin, Texas 78716.
