What are bats?


Bats are mammals, and they are placed into their own order called Chiroptera.  This comes from the Greek words meaning "hand wing".  As you can see from the pictures below, the wings of a bat are produced by taking hand bones and stretching them out.


This picture is from book The World of Bats, the flying goblins of the night by Klaus Richarz and Alfred Limbrunner


This picture shows the wing of a little brown bat flying in the lab at Ohio State where I went to graduate school

The Chiroptera have been a very successful order of mammals by almost any measure.  There are currently about 1100 species included in the order, meaning that about 1/4 of all mammals are actually bats!  Only rodents (with about 2500 species) have more.  There are about 5600 species of mammals, meaning that the vast majority of mammals are "rats & bats".

Bats are also successful when you look at where they live.  Bats can be found living on every continent in the world except Antarctica, and they can be found living as far north as the Arctic Circle.  They are also found on many isolated islands in the southern Pacific ocean, so when it comes down to it, there are bats just about everywhere!


This picture shows a bat's wing bones on the left and a bird's wing bones on the right.  Obviously bats have a very delicate skeletal system. 

Where did all these species come from?  That's a good question, and we really don't know for sure.  Unfortunately, the fossil record of bats is rather poor, since bats have developed a thin, fragile skeleton so that they can fly more easily.  The side effect of this skeletal system is the fact that it doesn't fossilize well.  The fossil record of bats is quite poor.  There are some old fossil teeth (about 60 million years old) that could be from bats, and there are complete bat skeletons from about 50 million years ago, but those fossils already look pretty much like modern bats, so we really don't know much about where they came from (not that people aren't looking, of course!)


What are the different kinds of bats?

Bats are divided into two main groups.  The Microchiroptera (small bats) and Megachiroptera (big bats).  The names are based on their relative sizes: Mega bats are generally larger, however, there are exceptions to this rule, since the largest Microchiropteran bats can be as large as some of the small Megachiropterans.


This is a Megachiropteran bat.  Note the large eyes and small ears.  See the page on  how bats navigate at night for some information on why those characteristics are important for these bats. 


This is a Microchiropteran bat.  Note the large ears and small eyes.  See the page on  how bats navigate at night for some information on why those characteristics are important for these bats. 

The Megachiroptera are sometimes referred to as "flying foxes" due to their dog-like faces.  They are confined to the Old-World Tropics (Asia and Africa) and they all eat plants, so they are also sometimes called "Old World Fruit Bats" or just "Fruit Bats".  Calling them by these last two names can be a little confusing, since there are Microchiropteran bats that eat fruit in the Old World, so I prefer not to use these terms to avoid confusion.

The Microchiroptera are found just about everywhere bats live in the world, and the diet varies from species to species.  The majority eat insects, but there are also species that eat plants and fruit, fish, snakes and lizards, frogs, blood (vampire bats) and even other bats!  With so many species to choose from, it's difficult to give exact details.  The majority of species in North America are insectivorous, but there are some nectar-eating bats in the southwestern US.

Basically, the question really should be what DON'T bats eat, since there are bats somewhere that eat about anything you can think of!

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