Monday, May 15, 2006

ECHOLOCATION IN BATS AND WHALES

Echolocation is the ability to see through sound. Echolocation is the use of ultra-high frequency sound for navigation. To understand how echolocation works, imagine an echo-canyon. If you stand on the edge of a canyon and shout hello you will hear your own voice coming back to you an instant later. Animals that use echolocation emit calls out to the environment. Echolocation is the method of sensory perception by which animals familiarize themselves to their surroundings, detect obstacles, and communicate with others. They use echoes to locate, range and identify the objects. Echolocation is used for foraging in various environments. Bats and whales are good examples of echolocation.

Most bats use echolocation or sound to find their food and navigate in the dark. Bats emitted high sound. Bats send out high frequency and listen for the echoes to locate their prey. Bats send out sound waves using their mouth or nose. When sound hits, an object echo comes back. The bat can identify an object by the sound of the echo. Most bats see pretty well. Echolocation help them to find their prey in the dark, most bat species have developed a navigation called echolocation. Bats are not blind they can also see in the dark by listening to the echoes of their high frequency calls, with this system they can pick up insects as tiny as mosquitoes. Bats that eat frogs, fish and insects use echolocation to find their prey in near darkness after emitting a sound, these bats can tell the distance, direction, size, surface texture and material of an object from information in the retaining echo.

Humans can not high pitched sounds that bats make. Most fruit bats use eyesight and smell for finding food not echolocation. When thousands of bats flying out of cave, they can use their echolocation of noise around. Different species of bats use different patterns of echolocation frequencies to find food and navigate. Whales is an another examples of echolocation.

Whales are large, and are aquatic mammals. Toothed whales produced sounds to communicate and echolocate. The whales send out a ray of sound. When the sound of echo came back. The sounds are picked up by the lower jaws. The lower jawbones are empty and filled with fat. These help the sound travel through the jawbone up to middle ear, inner ear and auditory nerve. The echoes are interpreted by the brain. Toothed whales use echolocation to sense objects. High-pitched sound is sent out by whales. The sound bounches off the object and some returns to the whale. The interpret this returning echo to determine the object shapes, direction, distance and texture.

Some whales may not use echolocation but may find their prey simply by listening. Toothed whales prey on fish, squid or marine mammals using echolocation. Echolocation helps an animal to navigate in water. The highest sound produces a more detailed of an object because the sound wave is shorter. A lower sound travels into water because the wave’s length is longer and can be used to detect distance or larger objects. Water is an excellent sound transmitter. Whales have capitalized on this water to compensate for reduced visions in cloudy water of the sea.

References

Roth, J. 2006. Echolocation. [Online]. Available: http://www.eparks.org/wildlife_protection/wildlife_facts/bats/echolocation.asp [2006, May 14]

Max, J. 1995. Fishin for facts: Echolocation. [Online]. Available: http://www.whaletimes.org/echolocation.htm [2006, May 14]
Linette Netshiheni
CSIR Pretoria
0001
Cell: 0820446442
Tell: 012 841 2133
Fax: 012 842 3676
tnetshiheni@csir.co.za
Weblog: http://tnesthiheni.blogspot.com/

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