Bats range in size across the different species, but tend to average about 5.5 to 19 cm in length (tip to tail) with a wingspread of approximately 15 to 38 cm. Most weigh between 3.5 and 60 grams (in the U.S.). Bats’ bodies are covered with hair varying in color from tan to black. Their wings stretch across elongated arm and finger bones.

Most bats have pointed ears and have the characteristic wings made of leathery skin; there is no fur on the wings. Bats also have teeth. When roosting, bats commonly hold on to their roost with their hind legs, hanging upside down.

Most bats are insectivores, feeding on insects at night. Bats will also frequent outside lighting where insects will be flying in warmer weather. They may also be found near swimming pools, as insects might be attracted to these areas.

Bats can be either colonial bats, living in colonies, or solitary bats, living alone or with just a few other bats. There is no queen bat in colonies; the bats just aggregate together.

Bats emerge in the early days of spring and leave their overwintering sites for summer homes. Typically, the first to establish nesting areas are the females ready to give birth. Because of their impending maternity, these new colonies are known as maternity or nursery colonies.

Baby bats are usually born during the summer months. The infant bats breastfeed until they’re ready to fly and hunt food on their own. The bats remain in this roost until the fall when it’s time to overwinter. Prior to leaving for winter residence, males begin arriving at these colonies in large numbers, ready to mate with the female inhabitants.

Winter hibernation is an instinct felt by all domestic bat species. Some travel less than 100 miles, while others travel thousands of miles from their summer roost. Equally fascinating is that some species winter in small groups, while others choose to gather in large numbers for their winter rest.

Many bats produce one litter of a few young per year, but number of offspring and mating habits vary depending on bats species.