- Vibrissa
Vibrissae (singular: vibrissa), or whiskers, are specialized
hair s, usually employed fortactile sensation, but can also refer to the stifffeather s near the mouths of somebird s. Vibrissae hairs commonly grow around thenostril s, above the lips, and on other parts of the face of mostmammal s, as well as on the forelegs and feet of some animals. Vibrissae are usually thicker and stiffer than other types of hair.Weldon Owen Pty Ltd. (1993). "Encyclopedia of animals - Mammals, Birds, Reptiles, Amphibians." Reader's Digest Association, Inc. pg. 18. ISBN 1875137491.] [ [http://medical-dictionary.thefreedictionary.com/Vibrissae Vibrissa] , medical-dictionary.thefreedictionary.com, undated (accessed20 January ,2007 )])]
In some mammals, the follicles of vibrissae are surrounded by a highly developed sheath of
muscle tissue which can be used to move them, such as in the case of whiskers found on cats, dogs and other mammals. Whiskers can grow to be extremely long; the length of achinchilla 's whiskers can be up to a third of its body length.Vibrissae offer an advantage to animals that do not always have sight to rely on to navigate or to find food, or when the usefulness of non-tactile
sense s is limited. Some animals, such as house mice, can even detect air movements with their vibrissae.A large part of the
brain of many mammals is devoted to processing the nerve impulses from vibrissae because it is important to their survival. Information from the vibrissae is transmitted and processed through thetrigeminal nerve into thebrainstem andthalamus before relaying to thebarrel cortex of the brain. Mammals use a great deal of energy to keep the follicles housing their whiskers warm and ready to use. Some animals - mainlyrodents - actively palpate their vibrissae, a process known as whisking, whilst others use them merely as passive sensors.References
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