Why Do Bats Turn Left When Exiting a Cave?

Bats exit their caves in whatever direction is open to them, using echolocation both to avoid collision and to locate food. It is a popular myth that they always turn left, a legend that may have first surfaced via an email campaign in the 1990s.

Bats are social creatures that generally roost in groups. Resting during the day, they arouse at night, circling within a cave before emerging in search of food. They often exit by following each other and so may appear to turn in a specific direction. They may return to their habitats to rest and re-emerge several times during a night feeding. The level of light from the moon and the length of daylight hours impacts their behavior since they return to shelter at sunrise.

All bats, however, do not live in caves. Bats may also live under the eaves of buildings, in rock crevices, beneath bridges and in trees. Of the order Chiroptera, which means "hand-wing," bats are the only known mammal truly capable of flight. Although they are able to see to some extent, they navigate primarily by emitting sounds that bounce off objects.

Echolocation enables bats to locate food and maneuver airborne with great accuracy and efficiency. According to Boston University's Center for Ecology and Conservation Ecology, experimental echolocation studies at Brown University and California Institute of Technology have developed a model sonar receiver based on a bat.