According to the researchers, this trait found in seals appears to be linked to their ability to learn vocalizations.
Scientific research has shown that seals can discriminate rhythm without prior training, which appears to be linked to their ability to learn vocalizations.
These are abilities that may have co-evolved in both humans and seals, scientists from the Max Planck Institute for Psycholinguistics in Nijmegen and the Sealcentre Pieterburen detail in the journal Biology Letters.
Evolutionary biologists believe that our abilities for speech and music may be related: only animals that can learn new vocalizations – such as humans and songbirds – seem to have a sense of rhythm.
“We know that our closest relatives, non-human primates, need to be trained to respond to rhythm,” explains first author Laura Verga of the Max Planck Institute. And even when trained, primates show rhythmic capabilities very different from ours, ”she details.
The researchers decided to test the rhythmic abilities of seals, animals known for their vocal learning abilities. The team first created sequences of seal vocalizations.
The sequences differed in three rhythmic properties: tempo (fast or slow, like the beats per minute in music), length (short or long, like the duration of musical notes), and regularity (regular or irregular, like a beat). metronome versus free jazz rhythm).
The team tested twenty young seals, held in a rehabilitation center before being released into the wild. Using a method from studies on human babies, the team recorded how many times the seals turned their heads to look at the sound source (behind their backs).
This looking behavior indicates whether the animals (or babies) find an interesting stimulus. If seals can discriminate between different rhythmic properties, they may look longer or more often when they hear a sequence they prefer.
The seals looked more often when the calls were longer, faster or rhythmically regular. This means that untrained and unrewarded 1-year-old seals spontaneously discriminated between regular (metronomic) and irregular (arrhythmic) sequences, sequences with short versus long notes, and sequences with fast versus slow rhythm.
“Another mammal, apart from us, shows rhythm processing and vocalization learning,” says Verga. This marks a significant advance in the debate regarding the evolutionary origins of human speech and musicality, which remain quite mysterious. As in the case of human infants, the perception of rhythm that we find in seals emerges early in life, is robust, and requires neither training nor reinforcement.”
Now Verga and her team want to find out if seals perceive rhythm in the vocalizations of other animals, or even in abstract sounds. They are also looking to see if other mammals display the same abilities.
