YouTube is filled with videos of dancing animals. There are dogs, cats, bears, ferrets, squirrels, dolphins, fish, and perhaps most famously, parrots. But despite all of the video evidence, many scientists remain skeptical.

The debate lies in a crucial distinction. While many animals are obviously capable of "moving rhythmically" to music, that's not the same thing as dancing. Dancing, according to scientists, requires an untutored, spontaneous response where the animal moves on the beat, matching motion to the music, according to NPR. By "untutored" and "spontaneous," that means the animal can't have a trainer or a human in the room that it is copying. The animal also can't spend weeks listening to the tune before perfecting its moves. In order to dance like humans do, the animal should be capable of finding the beat on its first listen.

Most scientists stubbornly hold to the belief that only humans truly dance, but few studies have been done to test the matter. That is, until now.

Enter Aniruddh Patel, a neurobiologist at Tufts University, and a truly remarkable cockatoo named Snowball. Perhaps you have seen some of Snowball's dance moves on YouTube. Here's a small sampling, Snowball's tribute to Michael Jackson:

It's an impressive display. So impressive, in fact, that when Patel first came across one of Snowball's videos himself, his jaw "hit the floor." Though he counted himself among scientists skeptical of such displays, he knew he had to meet this bird to find out for himself.

Patel had an experiment in mind. He brought with him a CD containing 11 different versions of the Backstreet Boys' song "Everybody." All of the versions were the same pitch as the original, but each remix used an altered tempo. 

For each version, Snowball danced gloriously. He bobbed, stomped and fluttered his fabulous crest feathers. Patel, meanwhile, took scrupulous measurements. 

So how did Snowball do? Well, he ended up being "on the beat" only about 25 percent of the time. While that may not sound up to snuff if you're comparing him to Justin Timberlake, it turns out that 25 percent is still better than pure chance. While Snowball wasn't a great dancer, he was, nevertheless, a dancer. Patel and team concluded in their paper that Snowball was officially the first scientifically validated nonhuman dancer.

Of course, this study raised the inevitable question: if Snowball can dance, then what other animals can dance? Adena Schachner, then a psychology grad student at Harvard, decided she would be the one to find out. She went back to YouTube and started watching. More than 5,000 video clips and lots of measurements later, and she had her answer.

It turns out that among all the animals purportedly dancing online, very few of them are actually dancing. Of all the videos she watched, Schachner found only 39 legitimate dancers, and 29 of them were parrots like Snowball (though 14 different species were represented). All of the rest of the dancers were Asian elephants. No other type of animal could pass muster. 

What makes parrots and elephants (and, yes, humans) so special? That answer remains mysterious. The next step in research will need to tackle that question. But at least humans can now rest assured that they aren't alone in their ability to pick out a beat, and dance.

So the next time you find yourself in need of a dance partner, you might want to consider a pet parrot. (A pet elephant is probably ill-advised.)

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Can animals really dance? Study reveals which animals can, and which can't
Study looks at YouTube videos of dancing animals and analyzes which creatures can keep a beat.