Pet whiskers are a navigation aid, early warning system, indicator of mood

Dr Leonie Richards, head of general practice at the University of Melbourne's U-Vet Veterinary Hospital, isn't sure of the origins of a saying that would be right at home in Gatsby's 1920s America. "Maybe people just think cats' whiskers are pretty cute and special," Dr Richards says.

She hastens to add that their value to our feline friends runs far more than skin deep -- they're also a crucial navigational tool, a pointer to impending danger and even an indicator of mood. Not to mention a great place to collect milk or food before going back for seconds.

Cats generally have a dozen whiskers arranged in four neat lines on each cheek, a few more where we have eyebrows, some under their chin and also on the wrists behind their front paws. "All of them basically serve the same purpose," Dr Richards says. "They're sensory, they help them work out where they are spatially."

Whiskers are a keratin product, the protein that makes up the outer casing of horns in animals ranging from cows to impalas. The follicles themselves don't contain nerves so in effect don't actually "feel" anything at all, but the point where they are embedded in the animal is packed with nerve endings fed by a strong blood supply. This, Dr Richards says, makes whiskers an ideal sensory organ.

"It's all about vibration, airflow and touch," Dr Richards says of these follicular feelers whose scientific name is vibrissae, from the Latin word vibrio, meaning to vibrate. "They use them to work out if they can squeeze themselves into a box or some other tight space, and to find their way around in the dark, similar to the way we use the touch receptors in our fingers to guide us in the same situation.

"They can detect airflow, which tells them if they're close to a wall or some other object in a dark room. The whiskers on the back of their paws are arranged to make up for short-sightedness -- if they've caught prey it gives them an idea of where the prey are in the feet."

Dogs use their whiskers in a similar but less pronounced way, and they don't have the back-of-the-paw feelers that cats are blessed with partly to help them navigate when scampering up trees. Dr Richards once had a dog owner come to her convinced the whiskers under their pet's chin were a chunk of plastic used for labelling that had become embedded in pooch's face and needed to be surgically removed.

A far more common whiskery conundrum is what happens to a cat if they're cut off?

"It makes them disorientated, it's harder for them to assess where their surroundings are," Dr Richards says, noting the part whiskers play in cats knowing they can safely leap large distances onto small or narrow landing areas. "Sometimes we have to cut them if the cat has for example an abscess in their cheek, you trim them to get a nice, clean surface. The whiskers will grow back in a couple of months, and the actual cutting of them isn't painful because they don't have nerve endings in them.

"But it can make them feel quite disoriented until they do grow back and even a little frightened. They do shed too, so you find the odd whisker around the place that's been naturally shed."

If a cat's whiskers are relaxed and droopy it's a good pointer to a calm, happy cat. "If the whiskers are pinned back up against its face it can mean they're quite fearful," Dr Richards says. "Straight forward can mean they're angry."

So what would happen if kitty was to overindulge and become so fat that its girth was greater than the span of its whiskers? "With a normal cat the whiskers will span out as far as their body can squeeze through," Dr Richards says. "If it's a really obese cat then they're not as useful. That's another reason to keep your cat slim -- so they don't get stuck!"

Editor's Note: This article was first published on Pursuit. Read the original article.