Published: 14 October, 2004

Crickets come out at night to avoid (most) predators

Why do crickets make noise at night?

When you hear crickets chirping at night, that is the sound of males trying to attract females. A female cricket may fly over great distances as she homes in on the calling song of a male. The journey can be risky, because it exposes her to predators, but it is necessary if she is to mate and lay eggs to produce the next generation of crickets. Hungry birds and mammals are major predators on insects during the day. Many insects, including crickets, avoid these predators by hiding during the day and becoming active only at night, when birds and mammals cannot see them. That is why you hear crickets mostly after dark. However, over millions of years, some mammals evolved special senses so that they could eat insects that fly in the dark. These are the bats, which find insects by echolocation. Hunting bats make sounds that are so high-pitched that we can't even hear them. These sounds echo off moths, crickets, and other insects. The bat hears the echo and uses it to find its food. Of course, the story doesn't end there. Many insects have developed the ability to hear the bat's high-pitched sounds, and can steer away from bats or even drop out of the sky when they hear danger. So the female cricket, avoiding birds by flying at night, also keeps an ear out for bats as she listens for her mate.