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Bats

Bats are mammals that can fly. Thats amazing! It turns out there are two kinds of

bats: microbats and megabats. The microbats, or true bats, use sonar and eat

insects, mostly. Megabats, also called flying foxes, on the other hand, dont use

sonar, and they eat fruit instead of insects.Diversity and Distribution

Bats are an incredibly successful order of mammals, with about 1240 species

[Wikipedia: http://en.wikipedia.org/wiki/Bat]. Thats one-fifth of all mammal species!

Wow! I am really surprised because they seem so fragileI thought they were rare

and endangered.

As the species count implies, they are also exceedingly adaptable. Bats make their

homes on every continent except Antarctica, in virtually every type of environment

except for the frozen northern extremity of Asia and North America. Some species

are endangered due to habitat loss and human influences, but the order as a wholeis plentiful and diverse.

Flight

The first thing you will notice about a bat is its wings. Bat wings are very different

than bird wings or insect wings. They are adapted from a mammal arm and hand,

with a thin membrane of skin stretched between the bones.

Bat wings Bird wings Insect

wings

Origin mammal forelimb reptile forelimb independent

of limbs

Lift provided by skin provided by feathers provided by

chitinous plate

Appearance skeletal fluffy, feathery stiff and

transparent

Stored wrapped around body folded on back folded or

pressed together, flat

Flapping just the fingers flap the whole wing flaps the whole

wing flaps

Size

Bats size is limited by two main factors:

- They must be light enough to fly.

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- They must be large enough to keep warm, since they are mammals, and must

maintain a high body temperature.

Here are the dimensions of some bat species:

Kittis Hog-nosed Bat, 29-34 mm in length, 15 cm wingspan, 2-2.6 g mass.

Giant Golden-crowned Flying Fox, 336-343 mm long, 1.5 m wingspan, 1.1-1.2 kg

mass.

Little Brown Bat, 6-10 cm long, 22-27 cm wingspan, 5-14 g mass

[http://en.wikipedia.org/wiki/Little_brown_bat]

Indiana Bat, 3-5 cm long, 24-27 cm wingspan, 7 g mass

[http://www.iowaagriculture.gov/livingontheedge/IndianaBat.asp]

Common Vampire Bat, 9 cm long, 18 cm wingspan, 57 g mass

[http://en.wikipedia.org/wiki/Common_Vampire_Bat]Grey-Headed Flying Fox, 23-289 mm long (avg 253 mm), >1m wingspan, 600-1000

g mass (avg 677)

Senses

Bats rely on their senses to find food, avoid obstacles in flight, and navigate their

homes. In some bats, sonar (echolocation) dominates, while others rely more on

sight and smell.

Sonar

Echolocation, also called sonar, involves bouncing sound waves off of objects and

listening for the echoes. Many kinds of batsmainly microbatsare expert

echolocators. They use their mouths to make sounds that are so high-pitched that

no human can hear them, and they listen for the echoes to bounce back to them.

Their echolocation is so sensitive and precise that they can find and catch insects in

the air and fly through complex caves without colliding with the walls.

Sonar is especially useful for hunting at night, since it doesnt require light. Most

insect-eating bats sleep during the day and come out at dusk to hunt. After all,

thats when insects are most active as well.

Bats adapt their sonar to the situation. For example, when hunting insects, they

start by sending out a broad pulse, every time they breathe out, that may last up to

one-tenth of a second. They listen for signs of insects. When they find one, they

chase it and, as they get closer and send out many more pulses that are much

briefer, as short as one five-thousandth of a second.

Sight

http://en.wikipedia.org/wiki/Little_brown_bathttp://www.iowaagriculture.gov/livingontheedge/IndianaBat.asphttp://en.wikipedia.org/wiki/Common_Vampire_Bathttp://en.wikipedia.org/wiki/Little_brown_bathttp://www.iowaagriculture.gov/livingontheedge/IndianaBat.asphttp://en.wikipedia.org/wiki/Common_Vampire_Bat

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Flying foxes, or megabats, have large eyes and good eyesight, and most species do

not echolocate. They eat mostly fruit, nectar of flowers, and pollen, which they find

by sight. They are most active during the daytime and at dusk, but their eyes are

good even in dark conditions, so they can also be active at night.

Insect-eating bats, however, often have tiny eyes that are not very sensitive. Theysupplement their sonar with them, but sight does not seem to be a primary sense.

Insect-eating bats, on the other hand, have small eyes, as they use the special

sense of echolocation for finding their food. However, they still use their eyesight

for avoiding large objects, gauging their height above the ground and finding their

way across a landscape by navigating between prominent landmarks. Although not

as well developed as a fruit bat's eyesight, their vision is particularly sensitive to

low light conditions. [Phil Richardson, The secret life of bats,

http://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.html]

SmellFruit-eating bats especially use their large, sensitive noses to find ripe fruit.

Some bats are frugivores (fruit eaters) and others are nectavores (nectar drinkers).

The highly developed sense of smell in many Old World fruit bats is due to their long

muzzles which have quite a bit of room for an abundance of olfactory receptors.

Many fruit-eating bats sniff out and consume mostly overripe fruit, keeping the tree

or bush healthy and fruit fly free. [Sandra Petersen, The Sense of Smell in the

Anumal World, June 23 2008, http://scienceray.com/biology/zoology/the-sense-of-

smell-in-the-animal-world/]

Smell, in addition to sonar, is a sense that works without light. Bats need it to findtheir way around caves and to tell the difference between other bats.

All bats have a good sense of smell. Old World fruit bats rely on it greatly to find

their food supplies, and their long muzzles are packed with smell-sensors. They are

able to detect the smell of rotting fruit or the scent of a flower downwind over a

considerable distance. Bats also use smell to identify their own youngsters from a

crche of apparently identical babies, often in pitch-black conditions. They have

scent glands that they use to mark themselves and other members of their colony,

and probably also their roosting sites. Many of these scents are odourless to us,

with our poor sense of smell, although some bats have a musky smell that we can

detect. [Phil Richardson, The secret life of bats, http://www.nhm.ac.uk/nature-

online/life/mammals/bats/session3/index.html]

Diet

Microbats

- insects

http://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.htmlhttp://scienceray.com/biology/zoology/the-sense-of-smell-in-the-animal-world/http://scienceray.com/biology/zoology/the-sense-of-smell-in-the-animal-world/http://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.htmlhttp://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.htmlhttp://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.htmlhttp://scienceray.com/biology/zoology/the-sense-of-smell-in-the-animal-world/http://scienceray.com/biology/zoology/the-sense-of-smell-in-the-animal-world/http://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.htmlhttp://www.nhm.ac.uk/nature-online/life/mammals/bats/session3/index.html

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A Thompsons big-eared fruitbat

[http://upload.wikimedia.org/wikipedia/commons/7/77/Big-eared-townsend-

fledermaus.jpg]

A flying fox has large eyes and nose, but small ears. It uses sight and smell rather

than sonar.

http://upload.wikimedia.org/wikipedia/commons/7/77/Big-eared-townsend-fledermaus.jpghttp://upload.wikimedia.org/wikipedia/commons/7/77/Big-eared-townsend-fledermaus.jpghttp://upload.wikimedia.org/wikipedia/commons/7/77/Big-eared-townsend-fledermaus.jpghttp://upload.wikimedia.org/wikipedia/commons/7/77/Big-eared-townsend-fledermaus.jpg

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A bat in flight displays its wings. [Jodi Torpey, Cute Creatures of the Night, Oct 28

2009, http://www.westerngardeners.com/cute-creatures-of-the-night-bats-part-

2.html]

The anatomy of a bat. The wing is stretched between the body and the elongated

fingers, as well as the legs and tail. [Sabine Deviche,Ask a Biologist, Bats,

http://askabiologist.asu.edu/explore/bats]

http://www.westerngardeners.com/cute-creatures-of-the-night-bats-part-2.htmlhttp://www.westerngardeners.com/cute-creatures-of-the-night-bats-part-2.htmlhttp://askabiologist.asu.edu/explore/batshttp://www.westerngardeners.com/cute-creatures-of-the-night-bats-part-2.htmlhttp://www.westerngardeners.com/cute-creatures-of-the-night-bats-part-2.htmlhttp://askabiologist.asu.edu/explore/bats