How bats use a compass to find their way at night

A European bat type can use the scatter patterns of sunlight to program its internal compass for hunting after dark - the first mammal known to do so, researchers said last week.

The only flying mammals, bats use echolocation, a form of sonar, to find their way around, but this only works at distances up to about 50 meters.

They leave their roosts in caves, trees and buildings at night to hunt for insects, often ranging hundreds of kilometers and returning before sunrise to avoid predators.