RESEARCH: Harbour Seals can change their voice to make them sound bigger

Scientific researchers have determined that Harbour Seals can learn to change their voice to make them sound bigger, and that the behaviour is not a result of their anatomy.

Bigger animals usually have deeper (lower pitched) voices than smaller animals, but the Harbour Seal (Phoca vitulina) seems to be different. The Harbour Seal seems to be able to learn to change its voice. 

The Harbour Seal, a marine (saltwater) mammal in the Phocidae family of seals is a pinniped (fin-footed, semi-aquatic mammal such as a seal, sea lion, and walrus) found in the Northern Hemisphere. It is found in the Atlantic Ocean, Pacific Ocean, Baltic Sea, and the North Sea.

Researchers at the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands, studied the sound of Harbour Seals. A previous study in November 2021, published in thePhilosophical Transactions of the Royal Society B, showed that pinnipeds can learn new sounds that they hear, so this Max Planck Institute research wanted to study the sounds that the Harbour Seal makes.

They studied 68 seal pups under 12 months of age at the Sealcentre Pieterburen in the Netherlands. They studied the vocal chords and seal sounds against their pitch and body size.

The researchers at the Max Planck Institute found that Harbour Seals deliberately move between low and high pitched sounds, which is learned behaviour.

Researcher Koen de Reus said that there was no anatomical structure that affected the vocal range of the seals, especially to modify their sounds. ‘Seals with as much as five kilograms difference in body weight produced similar sounding calls,’ he said. Hence, the researchers determined that the range of vocal sounds is learned. The researchers published their findings in the Journal of Experimental BiologyDIO:10.1242/jeb.243766.

The ability to learn, modify, and imitate new sounds is relatively rare, and found only in humans, elephants, bats, seals, whales, and some birds, said Koen de Reus. ‘The more we discover about animals’ vocal abilities, the better we can understand the evolution of human speech,’ he said. ‘It’s also another reason why it’s so important to protect wildlife.’

Photographer: Martina Nicolls


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