Hungry bats game
Bats use echolocation to find their food.
They send out calls when they're hunting at night and listen to the echoes that come back - they then use this information to 'map' their surroundings and work out how far away things are.
Bats can even use echolocation to tell the difference between objects and food - so they can avoid bashing into trees and hone in on a tasty insect instead :O)
Try it out for yourself - play the hungry bats game:
hungry bats