Parrots which can mimic voices can also groove as well as their human counterparts, implying an evolutionary link between the two capacities, a new study has found.
The study was led by Adena Schachner, along with co-authors Marc Hauser and Irene Pepperberg at Harvard and Timothy Brady at the Massachusetts Institute of Technology.
Schachner and colleagues closely studied Alex, a well-known African grey parrot which died recently and Snowball, a sulphur-crested cockatoo whose humanlike dancing behaviour had led to online fame.
"Our analyses showed that these birds' movements were more lined up with the musical beat than we'd expect by chance," said Schachner. "We found strong evidence that they were synchronising with the beat, something that has not been seen before in other species."
The researchers noted that these two birds had something in common: an excellent ability to mimic sound. "It had recently been theorised that vocal mimicry might be related to the ability to move to a beat," said Schachner.
"The particular theory was that natural selection for vocal mimicry resulted in a brain mechanism that was also needed for moving to a beat. This theory made a really specific prediction: Only animals that can mimic sound should be able to keep a beat," she added.
To test this prediction, Schachner needed data from a large variety of animals, so she turned to a novel source of data, the YouTube video database.
Schachner systematically searched the database for videos of animals moving to the beat of the music, including vocal mimics such as parrots and vocal non-mimics such as dogs and cats.
Schachner analysed videos frame-by-frame, using the same analyses applied to the case-study birds. Criteria included the animal's speed compared to the speed of the music and alignment with individual beats, said a Harvard release.
"The really important point is that many animals showed really strong evidence of synchronising with the music, but they were all vocal mimics," said Schachner. "Most of them were parrots. We found 14 different species of parrots on YouTube that showed convincing evidence that they could keep a beat."
The study was published in the recent issue of Current Biology.