Echolocation

Echolocation is the method of detecting objects by emitting a sound, receiving the echo and correctly identifying the location, size and structure of the object. In the animal world there are a number of animals that use echolocation to navigate and to hunt including bats and dolphins.

Echolocation in animals works by the animal emitting a sound from their mouths and then receiving the echo with their ears. Using this method they cand determine the distance to surrounding objects by using the time delay of the sound and can also determine the shape and direction by the amplitudes of the sound waves that arrive at each individual ear. This information is then interpreted by the brain thus giving them a mental image of their surroundings. Some humans that are blind have developed a form of echolocation by either emitting a sound with their tongue or by using a cane, and have explained that they develop a mental image of what they hear!

Bat Echolocation

The fact that bats use their ears to navigate rather than their eyes has been known since the 18th century although the term “echolocation” was not used till much later. All most bats have relatively good eyesight they operate within a niche in the ecological market which a good eyesight isn’t good enough. Bats hunt at night meaning that they can prey on animals such as insects, which tend to only come out at night, and it also means that they keep out of reach of predators which tend to operate in the day.

It has been found that Bats emit a sound at a frequency of 10-20 per second. Only when they detect a nearby prey do they increase this sound emission up to around 200 per second thus allowing them to detect immediately small changes in direction. This makes them very formidable predators at night. The study behind Bat Echolocation is very extensive and if you are interested in reading in more detail how Bat’s navigate then we recommend reading the scientific papers by D.R. Griffin, G Jones and R Muller.

Dolphin Echolocation

Dolphins and other toothed wales use echolocation to navigate and perhaps hunt as the visibility in the depths of the ocean can be very limited. Dolphins emit very high frequencies of clicks in a beam in the direction in which their head is facing. The echo is then received through fatty structures on the lower jaw and then passed through to the inner ear where the information is processed. Dolphins can resolve individual clicks of up to 600 per second!

Human Echolocation

More recently it has been known that humans that have gone blind from an early age are able to echolocate. They do this by making a sound with tongue, feet or cane and can then from the echo can determine a number of different objects by their structure, and can also identify the distance to them. Like our eyes, our ears can process a type of wave and after practise can identify small changes in amplitude. With the initial help of a person with sight or from someone that can already echolocate, someone using echolocation can remember and identify the echos of certain objects such as walls, posts, curbs, steps, tables, bushes, cars, and more. If you have seen the film Daredevil or read the comics, echolocation in humans is the same concept.