Why Do Roosters Crow?

Noah A. asks: Why do roosters crow in the morning?

rooster-crowNext to the bark of a dog or the gentle meowing of a cat, the crow of a rooster is one of the most recognisable animal noises on Earth; but why exactly do roosters feel the need to crow and is there any truth to the idea that they crow more (or only) in the morning?

Surprisingly, although chickens are one of the most ubiquitous (and delicious) animals on the planet, it wasn’t until 2013 that scientists definitively answered these questions.

First and foremost, it’s important for us to point out that roosters will crow at all times and in response to a range of seemingly innocuous stimuli, like the sound of a car or someone walking into their coop. This is because the crow of a rooster serves several functions. Along with being used as a warning of sorts to let other roosters known the boundaries of its territory, the crow can be used to communicate with other birds and sometimes to celebrate getting lucky; roosters really aren’t picky when it comes to excuses for crowing.

That said, although roosters have been observed crowing at all times of day and in response to even the most mundane of stimuli, they will indeed typically crow just before or at the crack of dawn. Because of the rooster’s tendency to crow at everything, for many years scientists and bird nerds (ornithologists) were under the impression that roosters crowing at day break were simply crowing in response to the changing levels of light, as they’ve been observed doing when they see car headlights or other artificial light sources. However, after years of anecdotal stories about roosters seemingly knowing when day break was about to occur, scientists at Nagoya University in Japan decided to see if this was just in people’s heads or if roosters really were anticipating, rather than reacting to, the sunrise.

In the research helmed by Takashi Yoshimura several experiments were run on roosters to answer these questions. To start, roosters were exposed to different environments for a couple weeks.  As expected, with all groups, the roosters crowed at all times of day in response to a variety of stimuli, like being fed.

So what about the mornings? First, a group of roosters were exposed to an environment where it was light for twelve hours, then dark for twelve hours, repeating for two weeks. As many have previously posited, the roosters really did anticipate the light, generally starting their pre-dawn crowing around two hours before the light was to turn on.

Another interesting observation was that the most dominate rooster was the one who would start the crowing off, lending credence to the idea that crowing is about marking territory and asserting dominance. As Yoshimura stated, “Our preliminary data suggest that the highest ranked rooster has priority in breaking the dawn, and lower [ranking] roosters are patient enough to wait and follow the highest ranked rooster each morning.”

In a second experiment, roosters were exposed to a constant, near-dark environment 24 hours per day. Despite this, Yoshimura and his colleagues noted that the roosters quickly settled into a “23.8 hour day” and would begin crowing the same time every day, just before dawn. The lighting didn’t seem to factor in.

Going further, when Yoshimura’s team tried to trick the birds by randomly exposing them to bright lights or loud sounds at various times, while this did induce some crowing, they consistently responded more strongly to the stimuli (crowed more) when it occurred around what would normally be dawn.

Yoshimura et al. concluded that the birds must have an internal body clock that tells them when to crow. Furthermore, due to the fact that roosters can’t be tricked into crowing at other times of day as strongly as they do around dawn, the researchers concluded that their “internal clocks take precedence over external cues.

As for why roosters seem to love to crow in the mornings, this isn’t fully understood, but is thought to be tied with the aforementioned notion of crowing being primarily about announcing territory and where a particular rooster sees itself on the pecking order.  This would also explain why roosters seem to crow in response to things like the sound of cars; they assume that such noises must be a potential rival and respond in kind. Similarly, when being given food, the crowing acts as a way for them to assert that it’s their food. And, of course, in the morning after a good night’s rest, they are re-announcing to the world their presence at the first opportunity.

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Bonus Facts:

  • Though it is often portrayed as being a behaviour exclusively observed in roosters, female chickens can and sometimes do crow.
  • Contrary to popular belief, both a wolf’s howl and a duck’s quack echo. (Wolves have even been known to use this to their advantage when hunting, making it sound like there are more wolves around than there really are.) Further, wolves do not howl at the Moon. This would give away their position and invite attack from wolves from another pack. Wolves have even been known to kill their own young who don’t learn when it’s appropriate to howl and when it is not. You can learn more about all of this here.
  • The crow of a rooster can be incredibly loud, as one farmer in England found out when her prized rooster, Big Bird, crowed so loudly half of the residents of the village she lived in complained about it keeping them awake.
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  • noelle

    OK i get this now, but would roosters crow if they were alone?

    • pockyfox

      Yes. They will crow even if they are the only chicken around. We have a single indoor/outdoor rooster. He helps the dogs guard the yard by crowing to announce that people are about or that something out of the ordinary is happening. He does like to crow happily in the mornings as well.

  • Cifey

    What if they moved to different time zones, do they adjust?

  • Alex

    I miss ole times being a kid in a town where there were no sissies complaining about any slightest sound or anything. The crowing of them roosters was delightful. And there were the other roosters answering to our rooster from far away as two to four blocks.

  • Sulaiman Almatar

    I am keeping hens roosters in my farm for few several years now and i noticed that roosters crow days and nights for no appearant reason. What i also noticed that other roosters in other farms always answer or my roosters will crow as an answer for hearing the crow for other farms far away. One rooster will crow and that will create a chain of crowing between roosters until reach far away roostets. This lead me to believe that one benefit of crowing is a caution sign saying “we are ok are you ok” but i always wonder how far the they connect.

  • Muhammad

    In fact, roosters crow for 2things. They crow when they see Angels and the second thing is when the time for praye comes. See your watch 5 times a day. I noticed that they crow to give notice of dividing night to 3 thirds and one hour before daw to alarm people to get up and pray at night.

  • Peter

    Excellent article; it was written and referenced very well! I thoroughly enjoyed reading it and I learned something new. Thank you for the great work!