US scientists have trained a seal to bob its head in time to music, in a study that the researchers say presents the first ever evidence that non-human mammals can keep a beat.
It was previously thought that only animals capable of vocal mimicry — birds and humans — could keep a beat in time to music.
In a study published in the Journal of Comparative Psychology, researchers from the University of California Santa Cruz said they had trained a Californian sea lion named Ronan to bob her head in time to songs, including tunes she had not heard before.
Previous studies had shown a sulfur-crested cockatoo could be trained to bob its head in time to a Backstreet Boys song across a range of tempos and that an African grey parrot and budgerigars could move in time or peck to the beat of a song.
“Here we demonstrate that a less vocally flexible animal, a California sea lion (Zalophus californianus), can learn to entrain head bobbing to an auditory rhythm meeting three criteria: a behavioural response that does not reproduce the stimulus; performance transfer to a range of novel tempos; and entrainment to complex, musical stimuli,” the researchers said.
“These findings show that the capacity for entrainment of movement to rhythmic sounds does not depend on a capacity for vocal mimicry, and may be more widespread in the animal kingdom than previously hypothesised.”
Ronan the seal was trained using fish rewards to dance in time to Creedence Clearwater Revival’s “Down on the Corner.”
She was soon also able to keep time even to songs she had not heard before, including “Everybody” by the Backstreet Boys, and “Boogie Wonderland” by Earth, Wind and Fire.
“Ability to find and keep the beat on two novel, quite different musical stimuli strongly suggests a flexible capability to entrain to complex stimuli,” the authors said in their paper.
The researchers also conducted a test to rule out the possibility Ronan was bobbing her head a split second after hearing the beat — rather than anticipating it and bobbing her head in time to the beat.
In this experiment, she bobbed her head in time to a metronome-like sound which was programmed to skip a beat. Ronan bobbed her head even even when the beat was missed.
Professor Adrian North, Head of the School of Psychology at Curtin University and a specialist in the psychology of music said the findings did not surprise him.
“There’s nothing inherently human about music. Across board, there is an awful lot of research showing that it’s not just humans that react to music in a general way,” he said.
“There’s evidence that whale song has a proper thematic structure, that lab rats prefer the Lennon-McCartney version of ‘Yesterday’ to one the researchers played themselves.”
Even human foetuses in the womb are capable of learning music, Professor North said.
“If you take a bunch of pregnant women and have them watching Neighbours every day, up to two months after they are born the children will react to the theme music,” he said.
Professor North said studies showed that the human aesthetic response to music happens in a the autonomic nervous system — the fight or flight part of the brain.
“It’s a basic part of the nervous system functioning, so it’s not surprising animals may respond in that way.
Professor Alan Harvey, Winthrop Professor of Anatomy, Physiology and Human Biology at University of Western Australia and an expert in music and neuroscience, said the seal study was interesting.
“There’s clear evidence of links between the auditory apparatus and circuits involved in movement, between the basal ganglia and the cerebellum and motor cortex. There are specific circuits between the parts that activate when you are tracking rhythm and tapping to a beat,” he said.
“Given there are some commonalities in the brain circuitry between mammals, it’s perhaps not that surprising that under certain reward conditions you may see this.
“There’s evidence that brain activity can be entrained by beat in humans, so it would be interesting to see if that could happen with non human mammals too.”