Zoo-Ology: The Why's of Whiskers

July 10, 2011 at 2:10 a.m.

A baby elephant seal shows off its whiskers. Seals use their whiskers to feel ripples in the water to track fish when they hunt.

A baby elephant seal shows off its whiskers. Seals use their whiskers to feel ripples in the water to track fish when they hunt.

By Judie Farnsworth

Raindrops on roses, vibrissae on kittens, or as the song goes, "whiskers on kittens."

Whiskers (vibrissae) are long, thick, flexible hairs that act as tactile (touch) sensors.

Animals work at keeping these wiggling, twisting hairs neat and clean and they are more important to an animal than you might realize.

They grow around the nostrils, above the lips and on other facial areas of most mammals. Some even have them on their forelegs and feet.

But, did you know whiskers are not just randomly arranged? There is a very orderly grid of arcs and horizontal rows on an animal's whisker pad. Front whiskers are shorter than the rear. Like hair, when one falls out, it is replaced.

They don't contain nerves, but can be sensitive to even slight air movement. Whiskers are rooted in a hair producing follicle in the skin, but a tactile hair follicle is unique. It's sealed by a tiny capsule of blood called a blood sinus. When a whisker is touched, it bends and the blood in the sinus is moved to one side or another. Very simply put, this triggers neurological sensations and reactions that send a message to the brain. A large part of the brain can be devoted to processing these nerve impulses.

In a number of mammals, particularly rodents, it's important that the follicles holding whiskers are kept warm and ready to use. Specialized muscle tissue helps move whiskers for extra information gathering. These animals constantly sweep and touch with their whiskers. This is known as whisking and a lot of energy is put into it. It may be like you moving the position of your fingertips when exploring with your hands.

Whiskers are particularly useful at night or dim light where seeing is difficult. A harbor seal may hunt in darker or murky water. Studies have shown their whiskers can actually track the path of a passing fish up to 35 seconds after it's gone. Seal whiskers are sensitive to shapes by feeling the ripples something leaves.

A cat's whiskers can work like a built in ruler. They're about as long as its body is wide. If they won't fit through an opening, neither will the body.

They can also indicate the animal's mood. An angry cat will hold its whiskers back tightly or relax them forward when curious or content.

Not to be left out, you may be happy to know that you, too, have vibrissae - inside your nose.

But, alas, rodents have an edge. Your vibrissae only act to block airborne particles. The next time you visit the Texas Zoo, be sure to admire all the wonderful whiskers waiting for you.

Judie Farnsworth is a longtime volunteer at the Texas Zoo specializing in educational programs.



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