The perfectly timed dance moves of a California sea lion named Ronan have shaken up a popular scientific theory about who's got rhythm.

Ronan really only has one dance move — it involves bobbing her head up and down — but the fact that she never misses a beat when bopping to pop hits like the Backstreet Boys' Everybody has her trainer very excited.

Peter Cook, a graduate student in psychology at the University of California, Santa Cruz, says Ronan is the first mammal other than humans that has demonstrated the ability to keep a beat.

In fact, he told CBC's As It Happens Thursday, a sense of musical rhythm was until recently thought to be something unique to humans.

That changed a few years ago when a Backstreet Boys-loving, dancing cockatoo named Snowball became a sensation on YouTube — and in the scientific community.

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Peter Cook was using Ronan as a healthy animal to compare to sick sea lions in another experiment. He noticed she was unusually bright and decided to try to train her to keep a beat. (University of California, Santa Cruz)

Snowball's talents led some psychologists to propose that a sense of rhythm evolved as an adaptation to boost vocal flexibility in animals with exceptional vocal talents, such as humans and birds that can mimic human speech.

"This theory was getting a lot of play, but no one had really tested it very thoroughly," Cook said.

He became interested in doing just that, and figured he knew just the right sea lion for the job. At the time, he was doing research at the Pinniped Cognition and Sensory Systems Laboratory at the University of California, Santa Cruz on how neurotoxins produced by algae affect sea lions.

Ronan, a sea lion that had been rescued off a California highway as a youngster in 2009, was the healthy animal against which sea lions affected by the neurotoxin were compared. Cook noticed that she seemed unusually bright.

On weekends, he started trying to train Ronan to bob her head in sync with a metronome. A few months and many buckets of fish later, he succeeded. Since then, Ronan has demonstrated the ability to find the beat in all kinds of music, although she's shown particular enthusiasm for Earth Wind & Fire's Boogie Wonderland.

"She moves a little sharper, there's a gleam in her eye," Cook said. "That one has been a real hit with her."

Cook says Ronan's rhythmic abilities may suggest that the ability to keep a beat may be common among a wide range of animals.