Of the roughly 5,400 mammal species on our planet, about 1,100 are bats. In other words, about one out of five mammal species is a bat. Biologists categorize bats by size, into two groups, megabats and microbats. Megabats live only in the tropics and are collectively known as flying foxes. These are the world's largest bats, weighing as much as 3.5 pounds and with wingspans of up to 6 feet. Microbats occur worldwide and include the planet's smallest mammal, the bumblebee bat ? it weighs about as much as a paper clip and has a wingspan of about 5 inches.

All of the 46 bat species that live in the United States and Canada are microbats. Most of our bat species are decidedly small, but their spread wings make them seem bigger. For example, the big brown bat ? common throughout the United States ? has a wingspan of up to 13 inches, but weighs only half an ounce.

Bats also are among the most varied looking of any animal group on Earth. With the exception of one hairless species, all bats have fur (they're the only creatures that truly make fur fly). Their fur ranges from stiff and sparse to long and fluffy, from pale blond or bright red to dark black or white. Some have long, swooping ears; others have bulbous or short, stubby ears or just wrinkled folds of skin; some have cute, little doglike faces; but most have peculiar facial features straight out of science fiction. Just read some of their names and you'll have an idea of the visual variety: long-nosed bat, short-nosed bat, spear-nosed bat, ghost-faced bat, mustache bat, horseshoe bat, hammer-headed bat, bulldog bat, leaf-chinned bat and slit-faced bat.

To read more about these amazing creatures, check out Terry Krautwurst's story, 'Fantastic Bats,' in the October/November 2005 issue of Mother Earth News.