Seals’ bodies act like loudspeakers when underwater, says new research

During the mating season when communication between male and female and seals gets ‘lively’ the seal’s body sends out noises as it swims underwater. Hayoung Jeon/PAP/EPA

Seals’ bodies act like underwater loudspeakers, according to new research.

Bioacoustic expert Dr Łukasz Nowak, a researcher at the University of Twente in the Netherlands, made recordings of seals at Hel Marine Station in northern Poland and found that during the mating season when communication between the male and female seals gets ‘lively’ the seal’s body sends out noises as it swims underwater.

Bioacoustic expert Dr Łukasz Nowak made recordings of seals at Hel Marine Station in northern Poland.czegoszukanauka.pl

To transmit sounds under water, seals need to change air vibrations into vibrations of their body, which are transferred to the water.

Nowak said: “Body surface vibrations can be used to generate sound in any acoustic medium, acting on the same principle as a loudspeaker.

“However, just as not every loudspeaker will work underwater, several conditions have to be met for this mechanism to be efficient.

To transmit sounds under water, seals need to change air vibrations into vibrations of their body, which are transferred to the water.Nic Bothma/PAP/EPA

“Unlike the sounds sent out by dolphins, seals’ vocal systems are similar to humans’.

“That is why seals inspired me in developing voice communication systems for divers.”

Last year it was found that wild grey seals can also clap their flippers underwater during the breeding season, as a show of strength that warns off competitors and advertises to potential mates.