Bats are small furry animals that fly. Their wings are thin
skin that stretches from the arm-like front limb along the
side of the body of the leg. The bat's small body looks
somewhat like a mouse's body.
Bats are mammals and feed their babies milk that is made in
the body of the mother. Unlike other mammals, bats are the
only type that can fly.
The world contains several hundred species of bats. They
are most common in warm climates, and the biggest bats live
there. But there are about 40 species of bats in the United
States. Four small kinds are even found in Alaska and
northern Canada. Some of the northern bats fly south when
winter begins. Others sleep through the winter in the
hollow trees, caves, and buildings where they make their
homes. Most kinds of bats are useful to mankind. They ear
vast numbers of harmful insects. Sometimes hundreds of
thousands of insect-eating bats live together in caves or
empty dwellings. The bat manure which collects on the
floors of such places, is a valuable fertilizer for plants.
A few kinds of tropical bats are harmful. Among them are
the large fruit-eating bats and the vampire bats. Fruit
eating bats may gather in orchards and destroy fruit crops.
Vampire bats live on the blood of other animal and human
beings. The bite of a vampire bat and the bites of other
kinds of bats m;ay transmit rabies. Most bats do not harm
human beings but people dread bats and have strange beliefs
about them. This is probably because most bats fly at night
and are not seen very often at close range.
Most bats are small. The little brown bat, which is common
in the United Stases is a good example of a common bat. It
has fur on the body, large naked ears, the rear legs have
claws, a tail membrane, and wings (Lauber 1968). The upper
arm of the bat is short while the forearm is very long
(Fig. 1). The wrist is very small and from it comes the
thumb and the four longer fingers. The thumb is short and
used for climbing or walking. The fingers are long and
thin. Interlocking the fingers is the wing. This
arrangement of having the fingers in the wing gives the bat
amazing flight maneuverability (Honders 1975). These bones
look similar to a human hand. They are connected by rubbery
skin to the bat's body enveloping all the fingers but the
thumb (Anonymous 1990).
Bats have a "sixth sense" called echolocation. This was
first proved by Donald Griffin. Bats produce ultrasonic
sound waves and then use the echo of the returning sound to
sense the world around them and in particularly to catch
insects. These sounds are usually out of the humans range
of hearing (Fellman 1993). This system is similar to that
of dolphins. The sound is in the form of clicks that
increase as the bat gets closer to the insect or whatever
it is tracking (Anonymous 1990).
Unlike humans, most insects can hear the bat's echolocation
sounds. David D. Yager of the University of Maryland has
found that the praying mantis has used this to its
advantage. When being pursued by a bat the mantis can hear
the clicks of the bat behind it and to avoid being eaten
goes into a series of evasive maneuvers. First they extend
their fore limbs and then they extend their abdomens .
After that, they go into a dive achieving a pace twice
their usual speed and if still being pursued will crash
into the ground to avoid being eaten.
Other insects also use hearing to their advantage (Amato
1991). For example, moths will also do amazing maneuvers in
attempts of escape, similar to the mantis. Tiger moths even
make their own ultrasonic clicks. It is not known whether
these are to startle the bat or to warn it that the moth is
distasteful (Fellman 1993).
Despite the insects great efforts to foil the bat's sonar,
the bat still catches its prey more than fifty percent of
the time (Fellman 1993). Some bats even have different
frequencies than insects cannot hear. The competition
between insects and bats will go on forever because they
will counter each other's counter measures by evolving new
strategies, and as James Fullard said "Evolution never
The food of bats usually becomes scarce during winter
months so some bats hibernate while others migrate (Honders
1975 and Bourliere 1995). When bats migrate they usually
move from the South to far North during the summer and they
return during the fall. Bats that hibernate prepare for the
winter by getting fat in autumn. Then they fall into a
sleep more extreme than their normal daily sleep. As in
most animals, when hibernating, their major bodily
functions, such as heart-rate and breathing, are suppressed
greatly. Bats are known to interrupt their hibernation
because they have been seen in the winter.
Disturbing bats during hibernation can be very destructive
(Pistorius 1994). This is because the bats have a limited
supply of energy. The energy used when the bat is awake is
huge compared to that when it is hibernating. Bats arise on
occasion anyway to groom, or sometimes take a flight
outside, and even to move to colder places, where they can
survive with lower metabolism and save energy. Repeated
awakenings can result in starvation during the late winter
from lack of energy stores. In an extreme case in Kentucky,
during the 1960's where a cave was a tourist attraction,
the population of 100,000 bats starved to death after being
awakened on several occasions.
Bats have internal fertilization and give birth to highly
matured young like humans (Lauber 1968, Honders 1975, and
Ezzel 1992). Most bats only have one baby a year. The bats
mate in the roost and have little or no courtship. The
pregnant mothers form separate nursing colonies from the
others. Some species like the Mexican free-tailed bat, who
migrate immediately after mating, produce a secretion that
preserves the male's sperm until they reach their new
roost. When their baby is being born the mother hangs by
her thumbs to a tree branch. Its tail membrane acts as a
cradle and the baby is born into it tail first. Then the
mother hangs by one wing and cleans the baby with the
other. It is then attached to the mother's teat where it
will hold on during flight. In some species the baby is
left at the roost when the mother is hunting, in others the
baby is taken along. In the species that carry their young,
the baby eventually grows too big for the mother and is
left in the roost. The bat then learns to fly and hunt its
prey by itself (Lauber 1968).
Some bats have developed special ways of adapting to their
surroundings. Though most bats eat insects, some feed on
fruit, nectar, small vertebrates, fish, and blood
(Bourliere 1995). The bats that eat fruit help disperse
seeds by eating and then dropping the seeds in their
droppings during flight. Those that drink nectar act like
hummingbirds pollinating flowers (Anonymous 1991). Bats
that eat small vertebrates along with insects and fruit are
often called false vampires. These bats eat lizards, tree
frogs, birds, rodents, and smaller bats. They kill their
prey by using their strong jaws and teeth to break their
neck. These bats have only about a two foot wingspan so
their prey tends to be small. Bats that catch fish fly just
above the water and catch the fish with its hind feet and
use its sharp claws to hold it. It then maneuvers the fish
to kill it by biting it (Novick 1973). The most famous of
bats is probably the vampire. The vampire bat drinks the
blood of large vertebrates when they are asleep. To help in
doing this they have developed large incisors, a
specialized tongue, and specialized saliva to prevent blood
from clotting. They are also able to move quickly on the
ground in case of their prey waking up and it is too full
of blood to fly away (Honders 1975).
There are many misconceptions about bats (Anonymous 1990).
People think that they are all dangerous because they carry
rabies. Less than one percent of all bats is infected with
rabies. Some people think that they can become entangled in
people's hair, but this is also untrue. Other people think
lots of bats drink blood but this is also untrue, only
three species of bats drink blood. These prefer cattle
blood and only live in Latin America.
Bats are actual quite helpful to humans (Van Dyke 1994).
Bats are important to many plants in the United States
because they help pollinate flowers. Most bats eat insects,
this is extremely helpful to humans. They help keep bug
populations low. Some bats, such as the little brown bat,
can consume about 600 mosquitoes in an hour. Bats also keep
the population down of other potential pests such as
leafhoppers, cucumber beetles, and June bugs.
Despite bats being helpful they can still be dangerous
under certain conditions (Anonymous 1988). Bat droppings,
or guano, are known to have spores and fungus in them that
cause Histoplasmosis, a lung infection, and other diseases.
Rabid bats can also be a threat because if one attacks, the
victim can easily be infected with rabies. If anyone ever
has to handle a bat, always wear gloves to prevent bites.
Bats are a good example of how an animal can evolve to have
amazing abilities. Bats have evolved to fly, use
echolocation, hibernate, sleep in the day, hang by their
feet, and many other things that individual species have
developed. Some large bats, called megabats, are even
thought by some scientists to be closely related to
primates because of their similar brain tissue. Bats are
highly evolved animals that have amazing characteristics
(Gibbons 1992 and Bailey et al. 1992).
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Department of Health. pp. 1-2.
Anonymous. 1990. Bats In Connecticut. Pamphlet from
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Anonymous. 1991. Warning From Bat Conservation
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