A male crouches, sharply drawing his breath to tighten his chest. The cape descending from his neck presses closely against his back. He turns his head upwards, fixing his eyes upon the female.
Suddenly, he puffs his chest, extending it up and out, before returning to his original position. Then, he flips his cape forward, up and over his body, slightly bowing his head. If he's confident that she's interested in his advances, he opens his cape, revealing two reflective blue-green "eye spots" just above his eyes. While holding this posture, he circles slowly around the female. If the female is interested, she takes a slightly submissive stance and turns in place. Their faces nearly touch as she rotates, constantly maintaining eye contact.
The setting for this elaborate courtship ceremony is not some medieval court or Dancing with the Stars. It isn't even a dance club or a crowded bar. This particular ritual takes place in the montane forests of Papua New Guinea. And the participants aren't humans, though they could be. They're superb birds of paradise, Lophorina superba, the cape in this case formed by a splendid plumage of black feathers.
People often suggest dancing as an example of activities that are uniquely human. Many species like the bird of paradise have various sorts of mating rituals, which could be described as "dances" by analogy. But dancing means something more specific: the "rhythmic entrainment to music". In other words, dancing isn't only moving the body in some stereotyped or over-learned fashion. Dancing requires that an individual moves his or her arms, legs, and body in sync with a musical beat. All human cultures ever encountered can do this, and until recently we thought this talent or ability was unique to our species. Until, that is, a celebrity parrot named Snowball knocked us off our place of perceived prominence.
Snowball became famous on the internet when videos were uploaded of the twelve-year-old cockatoo appearing to dance to a Backstreet Boys song. He seems to bob his head up and down in sync with the beat of the song. Sometimes he lifts his feet off his perch, occasionally alternating back and forth between his right and left legs. His crest also seems to raise and lower in rhythm with the music. Could it really be that humans aren't unique in their abilities to dance?
A sceptic might wonder if perhaps Snowball was simply imitating an off-camera human: an impressive ability in its own right, but not good enough to dance with the stars. But a neuroscientist named Aniruddh D. Patel, of The Neurosciences Institute, in San Diego, California, conducted an experiment to find out if Snowball was truly moving to the music, whether his dancing skills were purely the result of anthropomorphism on the part of human YouTube viewers, or whether it was simply imitation.
Patel took one of the tunes that Snowball was familiar with, a Backstreet Boys song called Everybody, and modified it so that the tempo could be sped up or slowed down from 86 to 130 beats per minute, without altering the song's pitch. The researchers took video recordings of the bird's movements while the songs were playing. After analysing their videos, they found that Snowball's dance steps were synchronized to the music. The parrot had moves, after all.
Signs of desire
Was Snowball an oddball, or is dancing widespread elsewhere in the animal kingdom? A second group of researchers ploughed through YouTube in search of data, and wound up with 1,019 uploaded videos that claimed to show non-human animals dancing. After a careful analysis, the researchers were left with evidence of dancing in fifteen species. Fourteen of those were, like Snowball, different kinds of parrot. The fifteenth example was an Asian elephant.