A sea lion named Ronan can now keep time with music as well as – and sometimes better than – people, according to a new study.
Ronan first made headlines more than a decade ago when she surprised scientists by nodding her head in time with music – a skill once believed to be uniquely human. Now, researchers say her sense of rhythm has not only held steady but improved.
At her most practised tempo, she consistently hits within 15 milliseconds of the beat. For comparison, a literal blink of an eye is about 150 milliseconds.
“No other non-human animal is as precise and consistent as Ronan is,” Prof Peter Cook, lead author of the study and a comparative neuroscientist at New College of Florida, told BBC Science Focus.
“However, Ronan didn't use to be as precise and consistent as she is now.”
Cook and his colleagues first trained Ronan in rhythm perception back in 2012, when she was just three years old. At the time, she was already the best non-human beat keeper on record.
But some scientists questioned whether her performance really matched that of adult humans. She showed more variability from beat to beat, and unlike human listeners, she tended to drift slightly ahead of the beat at slower tempos and lag behind at faster ones. (Humans, by contrast, tend to consistently strike just ahead of the beat.)
“Most human rhythm data is on adults, with decades of informal rhythmic experience — dancing, tapping feet to music, and so on,” Cook said.
“We tested Ronan when she was basically a kid… Now that Ronan is a fully grown adult sea lion, and now that she has had more practice and experience, how does she measure up to humans?”
To find out, the team asked 10 University of California, Santa Cruz, undergraduate students to mimic Ronan’s head-bobbing motion using a large, fluid arm movement. They then compared this with Ronan’s own performance at three tempos, including two she hadn’t encountered before.
She outperformed the students in consistency and accuracy, even landing in the 99th percentile of a model simulating 10,000 humans performing the same task.
The results challenge long-held assumptions that precise rhythmic synchronisation depends on vocal learning, a trait that humans share with some birds (such as Snowball, the Backstreet Boys-loving cockatoo) but not with sea lions.
They also suggest that rhythm perception may be more deeply rooted in the brain’s general timing mechanisms.
“Rhythm is pattern in time, and the natural environment is full of such patterns,” Cook said.
“Recognising rhythmic pattern can be very useful, because it allows an animal to predict what will happen next and organise its behaviour accordingly.
“For example, matching swim strokes to the period of the waves, grabbing a moving branch while swinging through the trees, organising your vocal output to match, cover, or interleave with that of other animals, and so on.”
Ronan’s rhythmic abilities may also pave the way for future studies. The team is now exploring whether she can track more complex, irregular patterns – the kind humans might find in jazz or folk rhythms.
They’re also testing other sea lions using game-based training, to find out whether Ronan is a one-off or just the first of many.
The real question, of course, is whether we’ll be seeing sea lions performing alongside musicians on stage any time soon.
“I believe you could get a sea lion to lay down a simple 4/4 beat,” Cook said. “When we've tested her with live-recorded music, Ronan dynamically adapts her rhythm as the band does, even with tempo changes.”
But before anyone signs Ronan to a record deal, there’s one tiny snag: “Sea lions only have one ‘hand’ – their mouth,” Cook added. “And they don't have good, precise flipper control on land of the nature required to work a hi-hat and bass drum.”
That said, Cook thinks getting her to perform alongside a live musician is definitely “something we’d like to try. Although I think there would have to be fairly regular breaks for fish.”
About our expert
Peter Cook is an associate professor of marine mammal science at New College of Florida. He studies animal cognition and comparative neuroscience in a wide range of species. Cook is particularly interested in finding novel, ecologically valid approaches to studying brain and behaviour outside of the traditional laboratory setting.
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