Bats have been regarded with superstition and fear in many cultures throughout history due to their nightly flying habits, strange appearance, and the tendency of certain species to feed on the blood of other animals. Over 1,200 species of bats exist in the world and less than five actually feed on blood. In fact, most bats are insectivores whose feeding habits are incredibly beneficial to humans. Large bat colonies can eat up to 500,000 pounds of insects each night. They hunt common pests, such as mosquitoes, flies, cockroaches, beetles, and moths, by using their large ears as radar dishes in a process known as echolocation.
The most common bat species in the United States are relatively small, with wingspans ranging from 9 to 15 inches. The little brown bat, big brown bat, Mexican free-tailed bat, pallid bat, and evening bat are most often encountered by humans. Each share common characteristics such as wings that are actually broad webbed hands, short legs with sharp claws, large ears, and the ability to make high-pitched squeaks that aid in navigation and communication. The fur of these bats ranges from light tan or yellowish in color to dark brown and black. Most North American bats have poor eyesight and relatively small eyes.
During the day, bats hang out together in groups numbering in the millions. They use their feet to cling upside down to the ceilings of caves, hollow trees, and buildings as they sleep. When dusk approaches, the bats awaken and fly out of cave mouths in large numbers. Darting over open fields, deserts, and yards, bats hunt throughout the night for flying insects. They often prefer to roost near ponds or lakes and rarely land on the ground since their small legs cannot support the weight of their bodies.
Bats are commonly found in attics and barns, as the mammals enjoy safe, dark places. Hollow trees and bat boxes are ideal places for the creatures to roost, as well. During summer months when bat pups are learning to fly, they accidentally enter buildings through open doors or windows.
For the most part, bats and humans peacefully coexist. One of the largest problems associated with bat populations is the droppings that accumulate. Although prized in some areas as a rich fertilizer, bat guano makes people sick when it collects in attics since it can harbor dangerous fungal spores, such as histoplasmosis.