A bechstein´s bat in flight at night. The mouth is wide open using echolocation for orientation.

What do bats, dolphins, and submarines have in common? They use the same technique to get a sense of their surroundings: echolocation. Here, an animal or a device emits sound waves, and listens for their reflections by objects in their surroundings. Based on what the reflected waves, or echoes, sound like, the animal or device understands its environment.

Animals that use echolocation emit high-frequency sound pulses, often beyond the range of human hearing. Bats, which have poor eyesight, use this ability to hunt and navigate in the dark while dolphins use it to locate objects and communicate underwater. Whales and some birds, such as the tawny oilbirds, swiftlets and the tenrec (from Madagascar), also use echolocation.

Humans have harnessed the principles of this ingenious technique to create devices like sonar and radar. Sonar’ is an acronym of ‘sound navigation and ranging’. It is widely used for underwater navigation, communications, and even as a method to find fish. Radar – an acronym of ‘radio detection and ranging’ – is used in aviation, weather forecasting, and military applications, to detect and track objects by bouncing radio waves off them.

More recently, engineers have used echolocation to develop smartphone apps that can create a map of a room to help people with visual impairments navigate their environs better.