Two famous parrots and a bevy of YouTube videos have now convinced scientists that people aren't the only ones who can groove to a musical beat.
Dancing has long been thought to be uniquely human. Toddlers will spontaneously bob along with music, but you never see dogs or cats listen to a tune and tap their tails in time.
So a couple of years ago, a neurobiologist named Aniruddh Patel was astonished when someone e-mailed him a link to a YouTube video of a sulfur-crested cockatoo named Snowball dancing to the Backstreet Boys.
"I said, you know, this is much more than just a cute pet trick. This is potentially scientifically very important," recalls Patel, who studies music and the brain at the Neurosciences Institute in San Diego.
Like A Cancan Girl
He got in touch with Snowball's owner, Irena Schulz. She runs Bird Lovers Only Rescue Service, a bird shelter in Indiana.
Schulz recalls that when Snowball's previous owner had dropped him off, he "also explained that Snowball dances." And along with Snowball, the man had brought the bird's favorite music.
He put on the Backstreet Boys and Snowball started to get down like there was no tomorrow, says Schulz.
"It was incredible the way that he would lift his legs way up in the air, like a cancan girl," she remembers.
Snowball swayed, he kicked, he bobbed his head — all in time with the music. Schulz put a video of the bird dancing online and it went viral, with millions of people watching him on YouTube.
"I felt like OK, this could be real," says Patel. But he wanted to test Snowball to see if the bird could really adjust his movements to match a different beat. After all, maybe Snowball just did a trained routine at one tempo that just happened to go with certain songs.
Patel's group took Snowball's beloved Backstreet Boys song and manipulated it with a computer. They slowed it down and sped it up. They sent the modified music to Schulz, who played it for Snowball and videotaped his reactions.
The videos show that yes, the bird will match his moves to the beat. For the slower versions, he sways his entire body like a pendulum. But, Schulz says, when the music gets faster, "he understands to adjust his movements. If he's going to sway, don't sway as much, just bob your head."
And when the beat gets really fast and he doesn't have time to bring his leg all the way up and down, she says, "he'll keep his foot lifted up and he'll just, like, do his wave, he'll wave his foot."
More Than 5,000 YouTube Videos
The results of this study are reported in the journal Current Biology, along with another scientific paper inspired by YouTube videos of dancing animals.
Adena Schachner is a graduate student in the psychology department of Harvard University. She says she was familiar with the idea that some people had made videos of birds supposedly dancing. And back in 2007, when she got interested in this, a famous African Grey Parrot named Alex lived at a nearby animal cognition lab. So she and her colleagues created some new music, something no bird could have heard before, and they played it for Alex.
"We were shocked, basically, when we put on these tracks and saw him bobbing his head what looked like to the beat," Schachner says.
Unfortunately, Alex died soon after. But Schachner realized that they could look for other dancing animals, with the help of YouTube. "We searched for 'cat dancing', 'dog dancing,' 'bird dancing,'" she explains.
She and her colleagues eventually analyzed more than 5,000 videos. "Imagine watching YouTube eight hours a day for a month," she says. "That's pretty much what we did. It was amusing for perhaps the first couple of hours."
In the end, only 33 videos really seemed to show creatures moving with a beat. There were 14 different species of parrots and one elephant species.
Dancers Are Vocal Mimics
Schachner says the important thing is that, like humans — and unlike dogs or cats — parrots and elephants are both known to be vocal mimics. They can imitate sounds. "And that's really striking," she says.
It means dancing may be a byproduct of an ability that evolved for vocal imitation and vocal learning. After all, to mimic a sound, you have to listen to it and its rhythm and then use that information to coordinate movement — to shape the way you move your lips and tongue.
All of these findings have convinced Tecumseh Fitch, an evolutionary biologist at the University of St. Andrews in Scotland who is interested in the origin of music.
"The capacity to extract a beat from sound and move your body to it was, until these papers, believed to be uniquely human," he says, adding that if parrots can really dance, all kinds of new experiments are now possible.
"For example, what genes are turned on while a bird is dancing?" wonders Fitch. "What genes are turned on by listening to a beat, versus listening to sounds that don't have a beat?"
And what would happen if a bird never heard any music for the first few years of its life? Could it still dance later on? That would be an interesting study, Fitch says, and one that could never be done on people.