We know that bats navigate and search for food by listening to how the sound waves they make bounce back. They can adjust the length and rate of their sound pulses to gather exactly the information they need about their environments. Recently, Discover Magazine revealed another cool sensory system of bats. They can adjust the width of their mouths to zoom in and zoom out.
Dr. Yossi Yovel and his colleagues at Tel Aviv University in Israel observed bats coming to a small desert pond for a drink of water. On their approach to the pond, bats had to fly through a confined space before entering a more open one.
By using cameras and ultrasonic microphones, researchers found that as bats flew through a confined space, they used a focused, narrow beam of sound. When they entered a big, open space, they used a wide beam to zoom back out. The bats made the adjustment by changing the width of their mouths.