Bats are nocturnal, which means they are awake at night and asleep during the day. They live in dark environments, such as caves. Because there is little light when they hunt insect prey, they rely on their sense of hearing. They do this through a process called echolocation. When a bat emits, or lets out, a sound, the sound bounces off the wall of the cave, an insect, or other objects in its environment. The bounced sounds reach the bat's ears. These bounced sounds give the bat information about the objects in its environment. The information allows the bat to know how close or how large an object is. This helps the bat locate its prey. Summarize: How does a bat use sound to find an insect?