Few animals have captured the imagination like bats. From superheroes to vampires, bats' unique characteristics have inspired fascination for centuries, but in real life, they play a critical role in maintaining a healthy ecosystem.

In addition to controlling bug populations, bats are a critical source of pollination. In the Southwest U.S. and in Mexico, they pollinate agave plants, making them essential for tequila production.

Bats have uniquely adapted to their environment. It's a common misconception that they're blind (and in fact they see three times better than people), but during the night they rely primarily on their ears. Their screeches allow them to echolocate, or create a sonar map of their surroundings.

With the heaviest wings of any flying animal, bats have developed unique acrobatics to land upside down in their resting position. With one wing pulled close to its body and the other extended, a bat uses inertia to swing upside down in only a fraction of a second.

Bat Appreciation Day, which falls on April 17, puts a spotlight on the flying mammals. The U.S. Department of Energy uses the seemingly playful holiday to highlight the issues facing the nation's bat populations.

Fatalities caused by wind turbines have become increasingly common since the increased use of wind energy. As many as hundreds of thousands of migratory bats may be dying every year because of wind turbines. Bats, which use sonar to navigate, collide with turbine blades when they fly too close.