Head-bobbing in pigeons theatre a vital role in just how they watch the world.(Image credit: Shutterstock)
In 1978, a team of researcher in a laboratory at Queen"s college in Canada clustered about a plexiglass box enclosing a treadmill … with a pigeon walking on it. The function behind this comical scene to be to shot and answer an age-old question: Why carry out pigeons bob their heads?
Head-bobbing is as much a feature of pigeons" identity as is their propensity to swarm united state at the slightest pointer that we could be harboring a snack. Bopping their heads together they stalk around pecking the ground because that crumbs, these birds it seems to be ~ to be grooving come some mystery beat, as if they"re all attending a quiet disco in the city square.
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But what"s the real objective behind this seemingly ridiculous motion?
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The 1978 treadmill experiment offered us the first an important insights right into that question. And also the research overturned one significant assumption in the process: Pigeons aren"t in reality bobbing your heads. Instead, they"re pushing them forward.
When the researchers in that research reviewed slow-motion footage, they found that over there were in reality two key parts come a pigeon"s head movement, i beg your pardon the scientists referred to as a "thrust" and a "hold" phase.
"In the "thrust" phase, the head is moved forward, relative to the body by around 5 centimeters <2 inches>," explained Michael Land, a biologist at Sussex university in the united kingdom who has actually studied eye motions in animals and humans. "This is followed by a "hold" phase, during which the head is kept still in space, which way that it move backwards loved one to the forward-moving body."
What we see as a "bob" is actually the head slide smoothly forward and also then waiting for the human body to catch up. Us perceive it together a bob because the movement unfolds for this reason rapidly.
"This wake up on average 5 to eight times a second as a pigeon is walking," Aaron Blaisdell, a professor of psychology who studies pet cognition, including that that pigeons, in ~ the college of California, Los Angeles, told Live Science. "That"s fast sufficient that, because that us, us don"t procedure it together the actual occasion unfolds and also our mental treat it favor a bob."
So, every this time we"ve to be ridiculing pigeons for your quirky gait, and it transforms out us were just seeing the the dorn way. And also the reason why pigeons practice this behavior, it turns out, is all about the way that these birds watch the world.
The researchers in the landmark treadmill experiment found that if a pigeon"s intuitive surroundings stayed fairly stationary around the bird as it strutted on the treadmill, the animal"s head didn"t bob. V reverse logic, this resulted in the central discovery: Head-thrusting help pigeons come stabilise their check out of the moving world around them.
"Keeping the head quiet in room during the "hold"" phases way that the picture will no be blurred by motion," land said.
In other words, a stationary head gives the bird a moment to visually procedure its surroundings while that waits because that its relocating body to record up; it"s choose hitting pause on the movement for a portion of a second. This tactic is useful due to the fact that it "enables lock to see potential food — and possibly, enemies," soil said.
If pigeons" heads relocated at the very same pace as their bodies, "they would have trouble maintaining a stable image of the civilization on their retina," Blaisdell explained; the bordering scene would certainly swim by in a confusing blur.
Blaisdell likewise shared an endearing anecdote: throughout research in his own lab, as soon as he picked up a pigeon and also walked forward with it, the bird quiet bobbed that is head, because the people was still moving around the pigeon also though the pet wasn"t relocating of its own accord.
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This intuitive trick isn"t simply a quirk that pigeon life. Human beings do a version of this too, except that rather of relocating our heads, we use rapid, jerky movements of our eyeballs to help fix ours vision as we relocate through space.
"Our eyes don"t move smoothly and also continuously. They in reality jump indigenous one place to another," Blaisdell said. These individual activities are called saccades, "and as soon as
In severe form, this is the flicking motion you see in someone"s eyes as they watch the scene unfolding external the window of a fast-moving train.
Pigeon"s eyes have the right to move approximately like ours, however the birds also have more-mobile heads than human beings do, so it renders sense that they"ve evolved head-thrusting as a an ext effective vision-stabilizing tool.
Bob, bob, bobbin" along
Pigeons might be the best-known birds because that this trait, but they aren"t the just ones that seem to it is in grooving follow me to an interior beat. "Most ground-feeding birds carry out head-bob," land said.
Chickens execute it, as perform birds prefer herons, storks and also cranes. A heron lurches its head front to pinpoint its prey, then brings its body in line v the impressively stationary head; this is the slow-motion version of what a pigeon is doing, Blaisdell said.
He additionally raised one interesting, and comical, idea. Birds are essentially modern-day dinosaurs, and also they share much in typical with their extinct dinosaur cousins. Recent discoveries have shown that many dinosaurs, even Tyrannosaurus rex, had actually feathers. "So, given the commonalities between modern-day birds and also dinosaurs, ns wonder if dinosaurs go head-bobbing, too?" Blaisdell said.
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Of course, that"s pure speculation, he cautioned. Yet it does leave us through the photo of a T. Rex, this bared, that head bopping wildly as it operation frantically about.