Hold a chicken gently on the ground, draw a line in the dirt away from its beak, and let go. The bird stays motionless, staring, for anything from a few seconds to several minutes. It is one of the oldest party tricks in the world, and it is usually called hypnotizing a chicken.
It is not hypnosis. But what it actually is turns out to be more interesting.
A very old trick
The earliest written account dates from 1646, when the Jesuit scholar Athanasius Kircher described what he called a marvellous experiment on the imagination of a hen. He tied the bird’s legs, laid it on its side, drew a chalk line from its beak, untied it, and found it stayed put. Kircher thought the hen imagined itself bound by the line.
The line, it turns out, is not needed. Simply holding the bird still, or turning it on its back, does the same.
It works on many animals
- Chickens and other birds
- Rabbits and guinea pigs, when laid on their backs
- Lizards and frogs
- Sharks, which go limp when turned upside down. Dogfish, lemon sharks and reef sharks all show it, and researchers use it to handle them safely.
- Insects and spiders that “play dead”
- Opossums, famous for it
What is really happening
The scientific name is tonic immobility. It is also called apparent death or thanatosis.
It is an anti-predator defence. When an animal has been caught and escape has failed, going completely still can save its life.
- Many predators are triggered to attack by movement, and may loosen their grip on prey that stops struggling.
- Some will not eat what appears to be already dead.
- A moment’s slackening gives a chance to bolt.
Researchers describe it as a response to being restrained that is strengthened by fear. The more frightened the animal, the longer it lasts. It sits at the far end of a sequence of defences: freeze, flee, fight, and finally, when caught, collapse.
The animal is not relaxed. Its body shows the signs of extreme stress.
Why it is not hypnosis
| Human hypnosis | Tonic immobility | |
|---|---|---|
| Trigger | Words, attention, willingness | Physical restraint, fear |
| State | Usually calm and comfortable | Extreme stress |
| Consent | Needed | None |
| Suggestion | Central | None |
| Imagination | Central | Not involved |
| Purpose | Chosen by the person | Survival reflex |
Hypnosis depends on language, imagination and cooperation. A chicken has none of these in the relevant sense. The only thing the two have in common is that somebody is lying still.
Do humans have it?
Yes, and this matters.
People who have been through terrifying events, including assault and serious accidents, often report being unable to move or cry out. This is thought to be the human form of the same response, and it is common.
It is involuntary. A person who freezes has not consented and has not failed to resist. Their nervous system has made an ancient decision for them. Survivors often blame themselves for not fighting back, and understanding this can lift a heavy burden of misplaced guilt.
Snake charmers and staring cats
Snake charming. The cobra is not entranced by the music. Snakes have limited hearing for airborne sound. It is following the movement of the pipe, held in a defensive posture.
Snakes “hypnotizing” prey. A folk belief. Prey animals freeze as their own defence.
A cat fixated on a bird is concentrating, not hypnotized.
Horse and dog “whisperers” use calm handling, pressure and release, and learning. Not trance.
Please do not try it
It may look harmless, but the animal experiences it as being caught by a predator.
- Rabbits. Welfare organisations advise against “trancing” pet rabbits. Studies have found raised stress indicators, and it can cause injury if the animal struggles.
- Chickens. It is a fear response, and repeated handling of this kind is stressful.
- Sharks. Used by trained researchers for brief procedures. Not something for tourists.
An animal that goes limp in your hands is not enjoying a cuddle.
So can animals be hypnotized?
Not in the sense that people can. Hypnosis as we understand it requires understanding suggestions and using imagination to act on them. Whether other species have anything comparable is unknown, and it would be very hard to test.
Animals can certainly be calmed, by gentle handling, a familiar voice, routine and trust. That is good animal care, and it has nothing to do with drawing lines in the dirt.
What it tells us about ourselves
The comparison is useful. Early mesmerists and some stage hypnotists thought of hypnosis as a kind of overpowering, something done to a passive subject, and pointed to the frozen chicken as proof. That picture is wrong. Human hypnosis is active, cooperative and imaginative. The frozen chicken shows what hypnosis is not.
The bottom line
“Animal hypnosis” is a fear reflex called tonic immobility: a last-ditch defence against being eaten. It is real, widespread and fascinating, and humans have a version of it too. It is not hypnosis, and it is kinder not to do it for fun.
Next in the series: Highway Hypnosis: Driving on Autopilot
This article is for general information and is not medical advice.