Escaped by a whisker – the importance of vibrissae
Whiskers are a very prominent and common facial feature found in mammals, fish, birds, and other non-mammalian species. With this widespread distribution and regular repetition throughout the animal kingdom, they must have a very important role, but what is it?
Whiskers or vibrissae are a type of stiff, functional hair used by many species to sense their environment.
They are sensitive tactile hairs that aid navigation, locomotion, exploration, hunting, social touch and perform other functions, and they have a remarkably different structure from the surrounding hairs.
Whiskers are longer, stiffer, significantly larger in diameter, and stand above the surrounding fur by a considerable amount.
In addition, they have well-innervated follicles, meaning each individual whisker has its own blood and nervous supply which feeds information back to the somatosensory cortex of the brain.
In cats, they use the information from their whiskers to aid spatial awareness, and it has been noted that cat’s whiskers move forwards as they are about to attack prey.
Dogs have an incredibly sensitive nose, and it is thought that the information from their whiskers adds another layer of information about their surroundings.
The whiskers around the eyes are more protective in nature, allowing the animal to avoid hitting their eyes on objects by touching them first with their whiskers.
Whiskers allow nocturnal animals, such as rats and mice, to ‘see’ in the dark. They help them avoid predators and find food.
A horse’s whiskers help them navigate their world. Indeed, they’re so sensitive to vibration and changes in air current they can instantly inform the horse about its environment; helping them avoid injury by detecting nearby objects, differentiating between textures, judging wind direction and identifying food from non-edible substances.
Horses have a blind spot beneath their muzzle, due to their eye placement on the side of their head, and so their whiskers are a vital aid to their vision.
Horses are more likely to suffer from facial injuries if their whiskers are trimmed or removed, as they have no means of judging the distance to objects immediately in front of their eyes or below their muzzle.
Many regulatory bodies in horse sport have banned the shaving of whiskers from around the eyes and muzzle for welfare reasons.
Anatomically and physiologically, it is proven that tactile hairs are part of a sensory organ and clearly differ from body fur. Without them, the sensory organ is not functional.
Trimming the whiskers is therefore not at all a cosmetic measure in the context of grooming, but constitutes a temporary amputation, which limits their sensory ability.
So next time you see an animal escape harm “by a whisker”, you may be more correct than you think.
• Lucy Richardson graduated from Edinburgh University in 2005. She started CedarTree Vets in August 2012 with her husband, Mark. They live at the practice with their two children, Ray and Stella, and their dog, two cats and two guinea pigs. She is also the FEI national head veterinarian for Bermuda