How do elephants make such low sounds? At last, scientists figure it out.
Elephants produce sounds like humans do, a recent study suggests. But their vocal cords are eight times longer and they can be heard up to six miles away.
Elephants' deepest calls can thunder up to 6 miles (10 kilometers) away. Now, researchers have learned for the first time how the massive animals produce these sounds.
It turns out that they do it in the same way that humans talk, pushing air through their vocal cords to make them vibrate. Elephants can go much lower than humans, however, because their vocal cords are eight times longer.
"The sounds the elephants make are off the piano keyboard," said study researcher Christian Herbst, a voice scientist at the University of Vienna, Austria. In fact, at less than 20 hertz in frequency, the main components of these ultra-deep calls aren't detectable to the human ear.
Until now, researchers weren't sure how elephants produced such low sounds. In fact, it's difficult to study voice production in animals in general, Herbst told LiveScience. In humans, researchers can insert cameras through the throat into the larynx, or voicebox, while people make different sounds. Animals tend to be less cooperative on that front, Herbst said. [Elephants: Photos of Largest Land Animals]
There are two ways to produce sound by vibrating the vocal cords (or vocal folds, as scientists call them). The first is called active muscular contraction, or AMC. With this method, the throat muscles actively contract to vibrate the vocal folds. AMC is how cats purr.