December 5, 2021

I, Science

The science magazine of Imperial College

A dancing young sea lion could be blowing the old theory of rhythmic entrainment out the water ...


There is nothing Ronan the Sea Lion loves more than a good bop along to the Backstreet Boys.  But her mysterious musical talents are getting scientists all of a tizzy. According to current theory, sea lions should not be able to keep a beat! So what on earth (or in sea) is going on?

Until recently, scientists believed that the ability to move in time to a rhythm, known as rhythmic entrainment, was restricted to humans and birds with a talent for vocal mimicry. This led scientists to theorise that the ability to keep tempo was a happy side effect of the capacity for complex vocal learning.

Then, in 2009, in a seemingly unrelated turn of events, a young sea lion was spotted stranded on the California coastline. She was rescued by the Marine Mammal Centre, who nursed her back to health and named her Ronan. Ronan hadn’t been getting on all that well in the wild, ending up stranded three times in her first year of life, so everyone decided she’d be more likely to survive in captivity.

It was in her new home at the Long Marine Lab that Ronan first met Adam Cook, now a postdoctoral fellow of Emory University. The pair clicked right away:

“From my first interactions with her, it was clear that Ronan was a particularly bright sea lion,” Cook enthused.

Intrigued by inexplicable tales of dancing birds, and the mysterious underlying cognition process behind them, Cook wanted to find out more. He set about trying to train his new sea lion pal to bop her head in time to a beat as a way of investigating rhythm in non-verbal mammals. Following initial training with a metronome, Ronan quickly found her rhythmical mojo, and was soon bobbing along to musical tracks. Eventually Ronan was able to pick out the beat and dance along to tracks she hadn’t heard before.

Discovering that mammals like Ronan, with no capacity for vocal mimicry, are able to pick up and move in time to a beat undermines the vocal mimicry theory of rhythmic entrainment.

Now efforts are underway to see what other creatures have an ear for music.  Cook suggests that “the neural mechanisms underpinning flexible beat keeping may be much more widely distributed across the animal kingdom than previously thought.”

Although parallel evolution is a possibility, this finding does indicate that rhythmical ability may have developed a lot further down the evolutionary tree than suspected. If it turns out that rhythm really isn’t a uniquely human and avian trait, this will revolutionise the way we study the neural process of rhythmic entrainment, which in turn might lead to insights into the adaptive advantages and mysterious cognitive processes underlying the human ability to rock out. Cook believes this could be a springboard for a  ‘renaissance’ in the study of rhythm. All thanks to a bopping young sea lion called Ronan.