At the age of three, Ben went blind from retinal cancer, a type of eye cancer. When Ben was about five years old, his mother noticed him making a clicking sound with his tongue that seem to help him understand his surroundings. This skill as normally used by animals with very sensitive hearing, such as dolphins and bats, for communication and to find food. They make sounds and listen for the echo made when the sound waves hit object and bounce back. Doctors tested Ben's hearing ability, but found it was normal. If Ben did not have superior hearing how was he able to use echolocation?