CATS
A body map in the dark
A cat's whiskers are packed with nerves at the root and help it move stealthily and react quickly. Cats also have whiskers above the eyes, on the chin and behind the front legs.
Read a cat's whiskersTHE SCIENCE OF WHISKERS
The moustache
that feels.
On most mammals, the moustache is a sense organ.
Compare whiskers
TOUCHat a distance
- Hair that senses
- Nerves at the root
- Moved on purpose
- A whisker is a feeler, not a frill
Whiskers, or vibrissae, are thick hairs set in follicles packed with nerves. Rats sweep them back and forth, seals read the water with them, and cats use them to move in the dark. Here is how they work.
Updated
THE SHORT ANSWER
The hair doesn't feel.
The root does.
A whisker works like a gramophone stylus:
it moves, and the follicle reads the movement.
SEALS
Following a wake
A blindfolded harbour seal told which way a fin had moved 35 seconds after it passed, with 70% accuracy. Seal whiskers can have up to 1,500 nerve cells each.
See the numbers
RATS
Whisking to explore
Rats sweep their whiskers back and forth about 8 times a second, and mice about 25, among the fastest movements mammals make.
Compare whiskersCOMPARE THE MOUSTACHES
Whose whiskers
do the most?
Pick an animal to see what researchers have found about its whiskers. The bar gives a rough sense of how much that animal's whiskers carry, from a handful to thousands.
Figures from The Physiological Society's Physiology News, BBC Wildlife's Discover Wildlife and the Journal of Experimental Biology seal study.
TWO NUMBERS FROM THE SEAL TANK
A trail in the water,
read by touch.
How long a seal could follow a fin's wake,
and how many nerve cells a seal whisker can carry.
35 seconds
Delay a seal could still read
A blindfolded harbour seal named which way a fin had moved with over 90% accuracy after 5 seconds and 70% after 35. After 40 seconds he lost the trail.
JOURNAL OF EXPERIMENTAL BIOLOGY, 2010
1,500 max
Seal, against 100–200 in rats and cats
These nerves report the direction, speed and duration of each whisker movement, letting the animal judge an object's position, size and texture.
NERVES PER WHISKER
The seal researchers said a fish can cover tens to hundreds of metres in that time, so whiskers compare well with the echolocation of whales and dolphins.
IF YOU LIVE WITH A CAT
What the whiskers
are telling you.
A cat's whiskers are a sense organ and a signal. The Carnegie Museum of Natural History suggests watching them, and leaving them alone.
Still and at rest
When a cat is relaxed, its whiskers are mostly still and at rest.
Bunched and flat
Whiskers pressed flat against the face mean 'back off' or 'I'm scared': give the cat some space.
Pointed forward
Whiskers angled slightly forward are a sign the cat is in hunting mode.
Never trim them
Cutting a cat's whiskers leaves it scared and disoriented. Whiskers are shed and grow back naturally.
AND US?
Why humans have
no whiskers.
Most mammals have whiskers, but humans, rhinos and some apes and whales do not. We still keep traces of the muscles once linked to whiskers in our upper lip. Animals with the best whiskers tend to forage in the dark or underwater, or climb at night.
Daytime, visual primates have fewer whiskers and no whisker muscles. One researcher suggests our sensitive, mobile fingertips may do the job whiskers do for other mammals, and being upright may make face whiskers less useful.
Questions
Questions people ask
What are whiskers made of?
Keratin, like hair. They are thicker and longer than ordinary hair, flexible, tapered and curved; aquatic mammals have thicker, stiffer whiskers. The sensing happens in the follicle at the root, not in the hair.
Do all mammals have whiskers?
Most mammals do. Humans, rhinos and some species of apes and whales do not, and some animals with whiskers, such as deer, horses and daytime primates, lack the muscles that move them.
How do seals use their whiskers?
To follow the swirling wakes left by swimming fish. In a 2010 study a blindfolded harbour seal could tell which way a fin had moved up to 35 seconds after it passed.
Can I trim my cat's whiskers?
No. The Carnegie Museum of Natural History says cutting a cat's whiskers leaves it scared and disoriented. Whiskers are shed and regrow naturally.
Why did whiskers matter in evolution?
Early mammals lived alongside dinosaurs and were often active at night. Whiskers gave them a sharper sense of touch for moving and hunting in the dark, and may have helped drive the expansion of the brain.
Where the facts come from
- The Physiological Society, Physiology News: Why don't we have whiskers?
- Discover Wildlife (BBC Wildlife): What whiskers are and how they work
- ScienceDaily / Journal of Experimental Biology: Harbor seals' whiskers as good at detecting fish as echolocating dolphins
- Carnegie Museum of Natural History: Holy Vibrissae Batman!