A lion or tiger’s roar may not be as frightening as it sounds, according to new research.
A lion or tiger’s roar can reach 114 decibels to someone standing a few feet away, 25 times louder than a petrol-driven lawn mower
In fact it’s little different to the sound of a crying human baby. Both big cats and babies make loud vocal noises to attract attention, say scientists. And both do it the same way, by vibrating similar types of vocal cords.
“Roaring is similar to what a baby sounds like when it cries,” said speech expert Ingo Titze, from the University of Utah in the US.
“In some ways, the lion is a large replica of a crying baby, loud and noisy, but at very low pitch.”
While babies cried for help, lions and tigers roared to lay claim to their territory.
“In both cases we hear loud, grating sounds that grab people’s ears,” said Dr Titze. “When a baby cries, the sound isn’t pretty. The sound is basically rough. The vibration isn’t regular.”
The same was true of big cats, which like babies had “very loose and gel-like” vocal cords that vibrate irregularly, he added.
The research, published in the online journal Public Library of Science ONE, showed that lions and tigers roar deeply because of the flat, square shape of their vocal cords.
Previous studies suggested that the large size of the vocal cords rather than their shape produced the distinctive sound.
The scientists analysed vocal cords from three lions and three tigers from Henry Doorly Zoo in Omaha, US, which had been euthanised because of disease.
Measurements were taken by attaching the vocal cords to levers that measured force and distance as the tissue was stretched. A lion or tiger’s roar can reach 114 decibels to someone standing a few feet away, around 25 times louder than a petrol-driven lawn mower.
“They roar with a sound that is frightening to people because it has this rough and raw quality,” said Dr Titze.
“Lions and tigers are deemed the kings of the beasts because of their roars. Imagine if they sang beautiful tunes and they were very low-frequency tunes. Who’s going to be afraid of that?”