Why Do Roosters Crow?
Cock a doodle doo!
My dame has lost her shoe,
My master's lost his fiddling stick
And knows not what to do.
English Nursery Rhyme
When your rooster crows at the break of dawn
Look out your window and I’ll be gone
You’re the reason I’m trav’lin’ on
Don’t think twice, it’s all right
"Don't Think Twice, It's All Right” - Bob Dylan
Wakefulness comes before the sun. I open my eyes to my dim bedroom, faintly lit by alarm clock glow. A silent breeze blows warm spring air through the open windows. Owls and coyotes have ceased their night music, and morning birds are still dreaming. All is still.
Then, the first morning sound floats up the hill from the barn, “Err-err-eeeeeerrrrr!” Emile is awake. “Err-err-eeeerrrrr!” A bit later, another call, a bit flatter and raspier, joins Emile's, “Err-err-err! Err-err-err!” Paul has added his morning commentary. Then the duet becomes a trio; with the addition of a more shrill and abrupt crow, “Errrrr-Er!” Snowball is chiming in. I swing my legs over the side of the bed and start my day as the sun begins to lighten the horizon.
By the time I get to the coop, the sun has climbed over the eastern edge of the world. Some of the hens are off the roost and scratching around the coop. The boys are all still on the roost and are continuing their jamboree. I open the coop doors and everybody hurries outside. The roosters carry their message to the great, wide world.
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Everybody knows that roosters crow in the morning. If you have roosters, you know that they also crow other times of the day. But have you ever wondered why they crow at all? What’s their motivation?
Tsuyoshi Shimmura has wondered about crowing and has endeavored to find some answers. Dr. Shimmura is a Japanese behavioral biologist and has studied an assortment of behaviors in chickens and other animals. Dr. Shimmura and his colleagues have tackled interesting topics such as:
“Do chickens raised by a broody hen behave differently than chickens raised without a mom?” (Short answer: “Yes!”) and
“Do chickens in small cages peck more than free-range chickens?” (Long answer: The amount of “beak related activity” (e.g. grazing, eating, drinking, preening, aggressive pecking, gentle feather pecking, severe feather pecking, litter pecking, and object pecking) stayed about the same regardless of how chickens were housed. But which type of beak related activity is influenced by their housing).
“Chickens and other birds display physiological and behavioral changes related to the length of day. Blinds birds also display changes. How can they do that if their eyes can’t distinguish light from dark?” (Because birds have photoreceptor cells in their pineal glands and quite amazingly, also deep in their brains.)
But what about crowing? What did Dr. Dr. Shimmura and collogues find out when they looked at that behavior? It turns out that “Err err errrrrr” means a bunch of different things in rooster lingo. According to Dr. Shimmura, Emile’s “Err err errrrr” can mean any of the following:
Territory: “Good morning, everybody! This is Emile crowing, and if you hear me, you know you’re in ‘Emileville.’ My rules apply here, and I’m in charge!”
Warning: “Here comes Randy with the scary garden cart! Have no fear hens! Gather round and I shall protect you!”
Pecking Order: “Hey, Paul, little buddy! You stay in line, or you’ll feel the wrath of my spurs, Okay?”
Food Availability: “Look, everybody! Here’s Randy with the bucket of scratch grain! You may thank me now!”
In other words, roosters are not irrational. They do crow for a reason. But there’s not just one reason.
Roosters do seem to crow more in the morning. Why? Opinion divides into three camps. Most people occupy the first camp. They have always assumed that the rising sun somehow stimulates roosters to crow. Most roosters inhabit the second camp. Roosters have always known that the sun rises because they tell it to rise by crowing. Folks who have spent time around chickens fill the third camp. They have noticed that roosters usually crow before dawn.
Roosters crow before dawn! Maybe the sun really does rise upon their command! Or is something else is going on? Do roosters have internal biological clocks cueing them to crow right before sunrise?
To find out, Dr. Shimmura’s scientists put roosters in an environment with artificial lighting. The roosters experienced twelve hours of light and twelve hours of darkness each day. Like clockwork, the roosters started crowing two hours before the lights switched on each day. Their own biorhythms regulated the timing of their morning crowing!
Further confirmation: The researchers put roosters into a completely dark environment. The roosters soon settled into a pattern of a 23.8-hour-day. They would crow at exactly the same time each day on that cycle.
Then the researchers subjected the roosters to traumatic situations; like scary lights and sounds. The roosters always responded by crowing, regardless of the time of day. But they would always crow more if these stimuli occurred at their “dawn”. The researchers concluded that “internal clocks take precedence over external cues.”
In another study, Dr. Shimmura’s team determined the pecking order in a group of roosters. Then they took note of the order of their crowing. The dominant rooster would always start crowing shortly before dawn. Then the second ranked rooster would crow; always after the dominant rooster. After rooster #2 crowed, the third ranked rooster would crow. And like dominoes the other subordinate roosters would begin crowing. One after the other in descending order of rank.
When the researchers removed the dominant rooster, the second-ranked rooster jumped right in to fill his place. He would crow before dawn and the other subordinate roosters would follow along behind, in order.
Dr. Shimmura and his colleagues determined the stimuli that caused crowing by studying roosters' behavior. But why do roosters crow? What goes on inside a rooster’s brain? Scientists have discovered the “crowing center” of a rooster’s brain in an area of the midbrain called the nucleus intercollicularis.
In this tiny brain corner reside bits of brain machinery called cholecystokinin B (CCKB) receptors. When the chemical cholecystokinin hits CCKB receptors, it’s like a finger hitting a button. Instant crowing!
Both hens and roosters have the gene to make CCKB receptors. But the gene is only turned on in the presence of testosterone, which is only present in roosters. Thus, roosters crow, but hens do not.
Dr. Shimmura and his team continue to do interesting work on chicken behavior. And that's good. The new knowledge will help us better understand the denizens of our coops. Maybe someday behavioral scientists will tackle the age-old conundrum. Why did that chicken cross the road?
I published the original version of this article on September 5, 2017
