A Report On Bats Essay Research Paper

A Report On Bats- Essay, Research Paper

A Report on Bats-

INTRODUCTION

There is an abundant amount of animal species in the

world. They all have adapted and evolved to survive in

their surroundings. Some have grown fins, others legs, and

still others wings. One of the animals that has grown wings

is the bat. The bat is a truly great creature. It has all

the characteristics of mammals while also possessing the

skill of a bird in flight.

There are more than 800 species of bats in the

world. They are of many different sizes, shapes, and

lifestyles. They live all over the world and have drawn the

curiosity of millions. Bats also have the unique feature of

echolocation that it uses to catch insects. Though other

mammals, like the flying squirrel seem to fly but actually

glide, the bat is the only mammal that can truly fly (Lauber

1968).

A BAT’S BODY

Due to the great variety of species of bats some

characteristics vary greatly, but the Little Brown Bat 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

it has the most distinguishing feature of a bat, 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).

Echolocation

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, then they extend their abdomens

which stop them. Then 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. This and other

insects also use hearing to their advantage (Amato 1991).

Moths 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 can 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

stops.

HIBERNATION AND MIGRATION

The food of bat 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

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