Monday, May 15, 2006

DISCUSSION OF ECHOLOCATION IN BATS AND WHALES

The term echolocation refers to the ability that bats and toothed whales posses and enables them to locate and discriminate objects by listening for echoes. Bats and whales use echolocation for different purposes, for instance hunting, navigating and to judge the distance of the object.

Echolocation in bats was found in 1930s that bats use high pitched sounds like natural sonar to locate food and navigate. Bats are capable of hearing the object when it bounces off. When an object the hits an echo sound come back. They can able to judge the distance, movement as well as size of the objects in their path. Some of the bats are able to send their echolocation through their sound and through their nose but the majority of bats use their mouth. They hold their mouth open as they fly.

Different species of bats uses different pattern of echolocation frequencies to find food and navigate. The scientists used detector like Anatbat bat to record echolocation pattern for use of identifying different bat species at night and inside the dark caves. Bats have the ability to see through sound. The bats can identify objects by the sound of the echo. They can even tell the size, shape and texture of tiny insects from its echo.

In the basic principles of echolocation, Bats sound the same way as human by moving air past their vibrating vocal chord. Bats use this echolocation process to gather information in order to see the world around them. Scientists believe that the strange noise that structure found in some bats serves to focus the noise for more accurate pin pointing of insects and other prey. A bat emits a sound wave and listens carefully to the echoes that return to it. The brains of bats process the returning information the same way. The bats are able to detect if the insects is on the left or right by using the sound. If the sound reaches the right ear before it reaches the left ear it means that the insects are on the right. The bats have ears which have complex collection of folds of the outer ear that help it to determine an insect’s vertical position. Echoes coming from below will hit the folds of the outer ear at different point than sounds coming from above, and so will sound different when they reach the inner ear of the bats.

Whales used echolocation mainly for navigation and hunting. Toothed whales have developed the capacity of emitting sounds that travel from foreheads and reflect off objects. Toothed whales echo late by producing clicking sounds and then receiving and interpreting echo. Toothed whales use echolocation to sense objects. Whales sent out high pitched whales, the sound bounces off, the objects and some returns to the whales. The whale interprets this returning echo to determine the objects shape, direction and distance. Toothed whales produce sound to overlapping functions. That is communicating and echo locating.

Whales produce lower frequency, longer duration’s tones such as groans and moans. These sounds are very loud and they do travel very far. Whales may be able to use the echo’s produced by these sounds to navigate and the echo’s returned as allow frequency sound bounce off features in the oceans basis such as islands, sea mounts and continental shelves, and this could easily give the whales information about its environment. The sound also gave the whales little information about the other in the closer surrounding area.

Echolocation plays an important role to the life of bats and whales. Both whales and bats are able to hunt food, navigate and to judge the distance in which the insects is located. They have capacity to emit sound that travel like waves and reflect object.

References

Wikipedia contributors. Bats [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 09, 00:20 UTC [cited 2006 May 09]. Available from: http://en.wikipedia.org/wiki/bats

Wikipedia contributors. Whales [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 08, 15: 15 UTC [cited 2006 May 09]. Available from: http://en.wikipedia.org/wiki/whales

Masiya Kedibone
CSIR Pretoria
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Cell No: 073 2519071
Tel No: 012 8412123
Fax: 012 842 3676
E-mail: kmasiya@csir.co.za

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