The Cat's Whiskers

This "high key" shot was taken in a 30 minute breather this afternoon when I went out to stretch my legs before afternoon consultations began. I almost failed to find anything to blip, but this cat appeared to save my bacon. .

Cat's whiskers are interesting - they are simply long thick stout hairs with no sensory capability whatsoever, and like other hairs they are shed intermittently, but they are useful sensory tools because the follicle of each whisker (which is the dimple of skin from which the whisker emerges) is very richly endowed with sensory nerves so that whiskers can be used like a blind person's stick to feel the world around. What's more, the whiskers have a motor innervation too - there are specialist muscles attached to the follicles which enable a cat to move his/her whiskers in an exploratory fashion - for example the whiskers are "brushed" forward when a cat is hunting.

We are used to talking of the five senses, but the sense of orientation cats get from their whiskers is rather outside our ken. The first cranial nerve carries the sense of smell, the second cranial nerve carries the sense of sight. Tactile information flows into the brain from the cat's whiskers via the fifth cranial nerve - the trigeminal. If you want to give your cat a tablet - try to avoid touching their whiskers - it's probably very unpleasant - the tactile equivalent of shinning a torch into the eyes.

It seems that as far as tactile sensation goes the cats whiskers are far from being the cat's whiskers the apogee of the biosphere. Mice and rats and other nocturnal rodents seem to devote a very large portion of their brain to information from their whiskers and also seem to perform a behaviour (called "Whiskering") which involves rapidly brushing the air and their surroundings with their whiskers (several times a second). This has been likened to "beating the night with sticks" and seems to have a role in scavenging and predation. Even more interesting I think is that marine mammals such as seals, sea-lions and manatee seem able to use their whiskers to follow fish and other prey through water and are said to be able to gauge the speed, size and direction of these prey by using their whiskers alone.