Though vocal learning or the ability to mimic sounds is the rarest trait among mammals, but researchers have found out that some species are capable of changing the pitch of their voice to sound higher or lower. This trait is considered as a crucial element of human speech only. Researchers have tried found out that if seal pups are capable of changing their pitch of their voices or not?
Wadden Sea Noise experiment
Researches have intently studied eight harbour seal pups who were 1 to 3 weeks old and were kept in Dutch Sealcentre Pieterburen rehabilitation centre. The researchers have first recorded noises from a nearby Wadden Sea of the rehabilitation centre to investigate properly if the pups could adapt their voices to noises in the environment.
Then the team of researchers played back the sea noises in three degrees of loudness to the pups. The team has also recorded the spontaneous calls of the pups’, to prove the fact that whether or not the pups can change their tone of voice to adapt to the sea noises.
The result of this experiment was, when the seal pups heard loud sea noises, they have lowered their own tone of voice automatically. The pups were able to keep a steadier pitch of voice when the noise level become intense. But to amaze us all, one seal has clearly showed the so-called Lombard effect by producing louder pitches as the recorded noise of the sea got louder. The Lombard effect is typically affected for human beings only, as people are used to raise their voices in noise to be heard and better understood.
The senior investigator of the researchers Andrea Ravignani commented “Seal pups have a more advanced control over their vocalizations than we have thought of until now. This control is already there at only few weeks of age of a seal. This is very surprising, as few other mammals are also capable of this technique.”
As a result, researchers have found out that young seals adapt to the noises in their environment by lowering the tone of their voice. This is their unique ability that they share with humans and bats.