Seals have a sense of rhythm

Human music and speech are dependent on rhythm. We are the only mammal with a sense of rhythm. A team of researchers led by the Max Planck Institute for Psycholinguistics in Nijmegen showed that seals can discriminate rhythm without training. Seals' ability to learn vocalizations may be related to their ability to play the drums.

Why do we talk so much? Evolutionary biologists think that our capacities for speech and music may be related, as only animals that can learn new vocalizations can have a sense of rhythm. Laura Verga says that non-human primate need to be trained to respond to rhythm. Chimpanzees show very different capacities when trained. What about other animals?

The seal rhythm.

Harbor seals are known to be capable of vocal learning. Sequences of seal vocalizations were created by the team. The sequence was different in three ways: pace, length and regularity. Infant seals would respond to these patterns.

Twenty young seals were tested before they were released into the wild. The team used a method from human infant studies to record how many times the seals turned their heads. Animals look at things in a way that indicates if they find something interesting. When seals hear a sequence they like, they might look longer or more frequently.

When vocalizations were long, fast or rhythmically regular, the seals looked more often. The 1-year-old seals don't have any training or rewards, so they discriminate between regular and irregular sequences.

The origins of the human race.

Verga said another mammal shows rhythm processing and vocalization learning. This is a significant advancement in the debate over the evolution of human speech. Similar to human babies, the rhythm perception in seals is robust and requires no training or reinforcement.

Verga and her team want to find out if seals can perceive rhythm in other animals' vocalizations or if other mammals can do the same.

More information: Laura Verga et al, Spontaneous rhythm discrimination in a mammalian vocal learner, Biology Letters (2022). DOI: 10.1098/rsbl.2022.0316. royalsocietypublishing.org/doi … .1098/rsbl.2022.0316 Journal information: Biology Letters