ECHOLOCATION IN BATS AND WHALES

Echolocation is the biological sound used by mammals such as bats, dolphins and whales to produce sound waves that encounter objects and these sound waves create a complex sound that returns back to their ears. Echolocation is some times known as Biosonar. Bats that echolocate are of the suborder Microchiroptera from the mammals order Chiroptera. The bats of Microchiptera suborder produce all manner of sound for echolocation and they do it for the purpose of catching prey such as insects.


The scientsts said that "not all bats echolocate, but bats of the sub-order Microchiroptera do echolocate" (4). Furthermore, members of this sub-order produce all manner of the sounds through echolocation. The sub-order of this group also does echolocate in order catch many preys and other many insects. On the other side" bats of moustached are said to be highly dedicated to the task of echolocation and are also said to be an excellent species" (4).


The ear of the human is thought to be unable to hear the echolocation abilities of the bats. Bats are also said to produce different types of sounds during the echolocation process for example, "mustached bat is thought to produce a biosonar sound consisting of a frequency which is stable” (1,3,4). Bats catch their prey by flying around, they do so by using their sonar signals as information about the food in the area. The sonar signals which are used by bats act like the waves of the sound, because sonar signals that “the bat produce return in the form of the echo, which the bat detect with auditory structures" (4).


On the other side whales use “echolocation to sense their objects and hunt their prey” (3). In echolocation highly pitched sound is sent by the whale. The sound is sent in this way, the sound bounces off the object and some returns to the whale. Therefore, the returning echo is interpreted by determining “the shape of the objects, direction, distance and the texture" (5). Teeth of the echolocation start with a series of the low-frequency. Their “echoed sound waves are from the flat-filled cavities of the bone that are at the lower jaw” (5). These sounds are "conducted through the bone to ear and the brains where as the location of the object is interpreted" (5). The whale can determine the distance to an object, its size, shape, the speed that the object is travelling and its texture.

It is also possible that the whales may use other types of sound to perform similar functions as the traditional sonar signals of the dolphins. While on the other hand "whales do not produce high frequency, broad band, short duration clicks" (5). They also produce lower frequencies as compared to the mustached bat. The echoes returned as the low frequency sound bounce off features in the ocean. In conclusion, one can say that the echolocation process is useful in bats because it seems unique in bats. This is because echolocation is only unique to the bats.


References:

1. Ketten, D. and Madin, K. 2005. How to see what whales hear. [Online]. Available from: http://www.whoi.edu/oceanus/viewArticle.do?id=5759 [cited 24 May 2006, 14:24]

2. Kruse 1996 Echolation in the bat. [Online].Available from:
http://www.npa.uiuc.edu/courses/physl490b/models/bat_echolocation/bat_echolocation.html [2006, May 24]


3. Roth J. 2006.Echolocation [Online].Available from:
http://www.eparks.org/wildlife_protection/wildlife_facts/bats/echolocation.asp [2006, May 24]

4. Wikipedia contributors. Echolocation [Internet] Wikipedia, The Free Encyclopedia 2006 May 07, 18: 16 UTC [cited May 15, 16: 10]. Available from: http://en.wikipedia.org/wiki/Animal_echolocation

5. Wikipedia contributors. Echolocation [Internet] Wikipedia, The Free Encyclopedia 2006 May 13, 00: 49 UTC [cited May 15, 16: 10]. Available from:
http://en.wikipedia.org/wiki/Whale


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