How do chickens move

That's why chickens keep nodding their heads when they run

Chickens keep nodding their heads while they run - or at least it looks like it. We explain why the animals move so strangely jerkily

"I want’ I was a chicken, "says the song by the Comedian Harmonists. However, the very idea that you have to jerk your head forward after every step is likely to make a person feel sick. What was nature thinking about exposing rural poultry to constant "swell"?

Well, viewed properly, it is a "sight walk" - the strangely jerky movement allows the chicken to take a closer look. If the chicken moves forward, it looks blurred - because its pupils are much more immobile than those of humans and also sit on the side of the head. Simply put, the chicken faces a problem similar to that which we face when looking out of the train window. The only difference is that the chicken's stare across the meadow is already too fast due to its staring eyes.

In truth, not really a real nod

This shortcoming is compensated for by keeping the head still for a long time until the eyes have fixed a stable image that can be processed in the brain. The rest of the body continues to move. Only when the image on the retina is stable does the head snap forward again to fixate on a new object. Strictly speaking, the head movement is not a nod at all. Because then the head would have to keep moving back and forth. It is an optical illusion created by the movement of the chicken's body.

With a similar delay tactic, the birds simulate spatial vision, which is otherwise hardly possible due to the lateral position of the eyes. In order to recognize the position of a tasty worm, first fix it with one eye, repeat this from a different angle and then calculate the individual images into a 3-D impression.

Read more: How animals see

#Subjects