Seal pups are one of the few mammals able to change their tone of voice and help to solve the mystery of the evolution of human speech
How do we humans learn to speak? How did language evolve from the first sounds of our species?
Studying how animals communicate can provide clues to human first words. A recent study of the wild howl of orangutans helped explain how the sounds evolved into words, depending on the route the call must take. In the case of orangutans, the predominant sound is the one that is best identified from a distance.
Human language may appear for over 50,000 years in Africa, and had an evolution, from some first sounds that could resemble the way of communication of other species.
The new study led by Andrea Ravignani of the Max Planck Institute of Psycholinguistics of the Netherlands, and published in Philosophical Transactions B, investigates the modulation of the voice tone when there is ambient noise. And they found that seal pups use it the same way we humans do.
In this video from the US Marine Mammal Rescue Center, we can hear the sounds produced by a baby seal.
Seal pups lower their tone to show their individuality
For this research, they observed eight common seal pups, between one and three weeks of age, at the Seal Research and Rehabilitation Center in Pieterburen, Netherlands. The objective was to know when they adapt their voices according to the sounds of their environment. At the end of the experiment, they were released.
They played audios from the Wadden Sea, in Dutch, with three different degrees of volume, from zero to 65 decibels. There was no water in the pool to avoid interference.
The researchers found that puppies voluntarily lowered their pitch when they heard louder sounds, rather than raising them to compete with the noise. They indicated that this means that puppies have vocal flexibility or the ability to change voice pitch as we humans do.
They found that animals that change pitch tend to reflexively raise their voices to combat loud noises, a phenomenon called the Lombard effect. Humans also do this when we argue with someone or converse in a confused environment.
Humans can reject the Lombard effect once we notice it and choose an appropriate tone for each situation. Ravinani’s team found that baby seals did just that.
Why do they lower the pitch when there’s so much noise? The study says that lower tones travel better in the wind, which helps the sound travel longer distances. Another reason for the team is that the seal pups do this as a way to express themselves and show their individuality.
However, scientists noticed that one baby seal raised its voice when exposed to a higher volume, while the others lowered their voices. The document states that it cannot be ruled out that seal pups increase the amplitude of their vocalizations in response to noise.
Control your vocal organs to speak and sing better
For an animal to have vocal flexibility, its brain must communicate in some way with the sound-producing center of the body or larynx. The human ability to speak and sing depends on the control we have over the vocal organs. Especially our larynx and vocal cords, notes the report.
Ravignani believes that “showing that seal pups do, spontaneously and without training, what our closest living relative, chimpanzees, cannot do, even after years of training, is absolutely amazing.”
If we put our hand on our throat while saying ‘a’, the vibration you feel is that your vocal cords vibrate about 100 times a second. If we didn’t have control over sound production, spoken language would be impossible, including learning new sounds in childhood, explains Ravignani.
We know the chaos that children sometimes form when they begin to pronounce their first words, which later become coherent sentences and organized and different thoughts. But how all evolution takes place is still a debate. Therefore, studying how seals adjust their tones could help solve the mystery of human speech patterns, the researchers say.
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