Scientists have believed that only humans can synchronize their movements with the beats in music, and follow the tempo when it slows down and speeds up. After seeing a YouTube video of Snowball, a cockatoo, strutting his stuff to his favorite Backstreet Boys song, psychologist Aniruddh Patel visited the bird and determined that he able to follow the beat, and reported his findings in Current Biology (video). Others have followed up reviewing 5000 YouTube videos of other species and found that 17% of the animals can follow the beat. Evidently those that imitate sounds are better able to dance. The ability to dance in time to music is called "entrainment".