This may be the most abundant bat in North America and is commonly seen in cities. They are small (3-4 inches long), with shiny dark brown fur. They are nocturnal and can be seen flying near wooded areas and water searching for insects, which they eat. Bats are the only true flying mammals (others species can only glide). Unlike birds, whose wings are made up of feathers, a bat's wing is made up of thin skin that is stretched between their fingers and body. Bats find insects using echolocation (similar to sonar). A single bat can consume over 3,000 mosquitoes in a night! During the day groups of bats roost in attics, hollow trees and caves. Female bats give birth to a single offspring each year, which they nurse and care for just like other mammals care for their young.