SCIENCE LAB SCHEME : BIG VOICES

 

BIG VOICES : These whales still use their vocal cords. But how? People have told stories of strange underwater sounds for thousands of years, but it took until the mid-20th century for scientists to pinpoint one of the causes :

Whales, singing and whistling and squeaking in the ocean.  The means by which some whales make these sounds has remained a mystery. 

A new study put forth a new explanation,  discovered thanks to a contraption that forced air through the voice boxes of three dead whales.

The larynx functions like an antechamber to the windpipe, or trachea with a flap of tissue called the epiglottis keeping food and drink from falling down the windpipe.

A bit below the epiglottis, mammals have evolved additional folds of tissue, called vocal cords or vocal folds, which produce sounds when air exhaled from the lungs causes them to vibrate.

When the land-dwelling ancestors of whales returned to life in the sea, '' they basically had to change the larynx, because when these animals are breathing on the surface, they need to expel lots of air really fast,'' said Coen Elemans, an author of the study and a professor of biology at the University of Southern Denmark.

Researchers attached the whales' two-foot long voice boxes in a series of pipes and pumped air through them.

At first, the voice boxes failed to make any noise. But when the larynx was repositioned so that a fatty pad connected to it was vibrating against the vocal folds, the lab heard the sounds of a vocalizing whale.

The World Students Society thanks Kate Golembiewski.