BATS!


Have you ever gazed up into the sky on a warm summer's evening as darkness was enveloping the land, and seen flying creatures darting and swooping through the air?  Birds, you thought at first, but as you watched, there was a fluttering, twisting, dropping motion to their flight that wasn't right for birds.  Bats! you suddenly realized.  And you were either pleased at the chance to observe them in action, or a little frightened as myths of Dracula and vampires, coupled with concerns about rabies, came to mind.

Or maybe you have never seen them before, but you've still heard all the bad things about these "scary creatures".  You've heard that bats are blind, that they get in your hair, that they are dirty, rabid, blood-sucking creatures (are they birds or mammals?) that YOU would never want anything to do with.

Through the ages, bats have been the stuff of myths and legends, misunderstood and feared, even though they play a vital part in many ecosystems around the world.  But what are they?


Mom and Nursing Pup


Straw-colored Bats from Africa
WHAT ARE BATS?
Bats are flying mammals.  They are covered with fur, give live birth, and nurse their pups with nipples located on the sides, under their wings.  But what makes them unique among mammals is the fact that not only are they perfectly designed for hanging upside-down, like the sloth, but they can also fly.  They are the only flying mammal.  Flying squirrels and flying lemurs can only glide; only bats actively fly.

Bats are not rodents.  Although many people think of them as mice with wings, and indeed, the members of the genus Myotis (including the common Little Brown Bat, Myotis lucifugus) are called mouse-eared bats, they are very different.  They only have one pup per year (a few have twins or up to four), and can live eight to thirty or more years, depending on the species (there are over 900 of them).

Bats' wings make them so unique that they have been placed in their own order, Order Chiroptera, meaning "hand-wing".  As the name implies, their wing consists of an arm that ends in a wrist with a thumb and four separate fingers which are webbed with skin, and form the ribs of the wing.  By contrast, a bird's wing possesses a greatly-reduced number of "finger" bones.  While the thumbs of most insect-eating bats who catch their prey on the wing are small and weak, the big fruit-eating bats called flying foxes (because of their fox-like or dog-like face) have very long and strong thumbs with curved "thumbnails" like claws, which they use for climbing around in trees and gripping fruit.  Bat fingers have the same number of bones ours do, but they are proportionately much longer.  The last bone of the "middle" finger of the Rodrigues bat (Pteropus rodricencis), for example, is actually folded behind the elbow when at rest.

When bats aren't flying they fold their fingers back along their forearms out of the way.  When bats extend their fingers and arms, their wings are ready for flight.  By shaping their "hands" they control the shape of their wings.  Slow-motion photography has actually shown insect bats scooping up insects in their wings and tail membranes, transferring them to their mouths in mid-flight.

Look at your fingers and forearm; try to fold your fingers down against your arm, and try to imagine your fingers extending past your elbow.  But don't forget to leave your thumb extending forward for gripping and climbing.  Then there is the webbing that connects all the fingers except the thumb, and extends all the way along the arm and body to the ankle, and in most species continues to envelop all or part of the tail.  Truly they are unique mammals.

The order is broken down into two sub-orders, Megachiroptera, the "big bats", and Microchiroptera, the "little bats".  The old-world fruit bats, the flying foxes, are megabats.  The insect bats and all the other kinds are considered to be microbats.  The system breaks down sometimes, however, since some micros, like the little Jamaican fruit bat (Artibeus jamaicencis), eat fruit, and one flying fox, the Queensland blossom bat (Syconycteris australis), weighs only half an ounce.

WHAT DO BATS EAT?
Bats' diets are quite varied.  Most bats eat insects, and are equipped with a very sophisticated "SONAR" or echo-location system for locating their meals.  The next largest group are the fruit eaters, that usually don't echo-locate, as fruit doesn't fly very fast.  Then there are bats that eat fish, bats that eat frogs, bats that eat small rodents and even other bats, and finally there are the famous vampire bats that drink only blood, either from birds or from large mammals.


Do Bats Smile?

WHAT ARE THEY LIKE?
Bats are soft, gentle animals, not aggressive (unless fighting over food or harem rights).  They are clean animals, washing themselves with their tongues like a cat.  They are curious and intelligent, easily trained.  As a volunteer at the Oregon Zoo in Portland, Oregon, USA, I have sometimes reached out to fruit bats in our exhibit, and had them reach back to me, trying to touch and smell me through the glass.  Amanda Lawler, founder of Bat World, in her book, Bat in My Pocket, describes her experiences taking care of sick or injured bats, and it is very clear that those little creatures were quite intelligent, learning how to train HER to do what THEY wanted.  Merlin Tuttle, founder and head of Bat Conservation International, found that he could train wild-caught bats to fly on command for staged pictures in only a few hours.

DO THEY ALL CARRY RABIES?
No, they do not.  The incidence of rabies in bats is about one-half of one percent, the same as for other larger mammals like foxes, skunks, raccoons, and squirrels.  You can actually be in more danger of rabies from dogs and cats that haven't been vaccinated, as unlike larger animals, bats are not agressive when they get sick.  If you find a bat on the ground or acting strangely, leave it alone (or wear heavy gloves or other protection), as it could have rabies.  Otherwise you have nothing to fear when bats are around.v A bat in the house does not mean it is rabid; it probably came in an open window or other opening, looking for a place to sleep.  It is at least as scared of you, a huge monster, as you are of it.  Gently capture and release it, or encourage it to find an open window or door to leave.  Millions of people have come to Austin, Texas, USA, to watch thousands of bats fly out at dusk every night during the summer from under the Congress Avenue Bridge, and there has never been a single case of rabies there.


Modern Bat Skeleton

Note Finger Length


Oldest Bat Fossil

Note Finger Length

WHERE DO BATS COME FROM?
Baby bats come from momma bats.  This may sound like a "well, DUH!" statement, but the point is that there is NO SCIENTIFIC EVIDENCE that bats evolved from any other kind of animal.  There is a lot of speculation, guessing, and assuming, but the actual observable evidence (genetic and fossil) is that bats come from other bats.  For a fuller, documented treatment of this subject, see Bats and Evolution.

WHY ARE THEY IMPORTANT?
Insect bats improve our quality of life, and reduce both crop damage due to insects and the incidence of disease spread by insects.  The common little brown bat can eat up to 600 mosquito-sized insects per hour.  The Mexican free-tailed bats (Taderida brasiliensis) from Bracken Cave and other smaller caves nearby in Texas, USA, eat an estimated 250 tons of insects every night during the summer, saving many farmers' crops.  Malaria, spread by disease-carrying mosquitoes in many parts of the world, would be much more of a problem were it not for bats.  Can you imagine what the world would be like WITHOUT insect-eating bats?

In tropical rain forests, bats play a vital role in the pollination and seed dispersal of fruit trees as they visit the flowers to gather nectar, then come back when the fruit is ripe to eat it.  In many South Pacific islands, bats are the only pollinators, as there are no bees.  Many economically-important fruit trees, like figs and mangos and the famous durian in Southeast Asia, would not get pollinated were it not for bats.  Bats pollinate wild bananas, from which we derive the cultivated varieties.  Seeds passing through a bat will sprout more quickly than otherwise, and bats (unlike birds) often drop them away from the trees, where they can grow into new trees.  Were it not for bats the tropical rain forests would soon disappear.

In many desert regions, bats play a major role in the pollination and seed dispersal of cacti and other desert plants.  In the southwestern United States and Mexico, for example, bats are the major pollinators of the saguaro cacti, and the exclusive pollinators of the organ-pipe cacti and of the agave or century plants (from which tequila is made).

Even the dreaded vampire bat, with seemingly no redemptive value, is aiding medical science.   Its saliva is a very powerful anticoagulant, and a synthetic version could be very useful in preventing or treating heart-attacks.


If you would like to find out more about bats than the brief(!) overview here,
or if you would like to become involved in bat conservation at home or around the world,
Bat Conservation International has much more information available, with links to web sites all over the world,
and a beautiful full-color quarterly magazine called "Bats".
Check them out!

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