Forest Speaks

Bats do something we can't do: they navigate using sound

The bat emits sounds that are so high in frequency that we can't even hear them.

The sound bounces off of objects (like insects or trees) and comes back as an echo that the bat uses to tell where the objects are by nothing the time that it takes for the echo to return. This is called "echolocation".

Elisabeth Kalko (visiting scientist) uses a special tape recorder to record the sound that a bat is making.

The bat makes long signals as it seaches for an insect. It makes many short signals in order to locate the insect precisely. After capturing it, the bat produces long signals again.

She also uses a camera hooked up to multiple flash units to take a series of picture of the bat`s movement as it catches an insect.

Each bat species has a unique signal that depends upon where it lives and what it eats.

Now scientists can record the calls and identify species of bats that fly too high to be trapped in mist nets.

Notice that bats in environments full of obstacles make more and shorter signals. Bats in open environments emit longer and fewer signals.