Identify hyenas with laughter

For human ears, the laughter of every hyena in a herd sounds the same: tall and dazzling, bizarre and crazy. But each hyena has a different laugh that conveys information about its age and location in its herd . This is the result of behavioral neuroscientists at the University of California, Berkeley and Université de Saint-Etienne in France. They have found a way to identify hyena by selecting characteristics in their laughter.

Hyenas do not laugh when they're having fun. Besides, biologists also realized that hyenas emit sounds when they compete for food. Laughter is an expression of anger, this sound comes from a lower position when it is overwhelmed by another child of the same age.

Two hyenas at Amboselia Kenya.
(Photo: iStockphoto / Stefanie Van Der Vinden)

In order to understand the meaning of laughter, Nicolas Mathevon and his colleagues analyzed the sound produced by 17 spotted hyenas. Scientists have developed a kind of algorithm that successfully identifies each individual in the herd by looking at the timbre and characteristics of a certain note in laughter. Mathevon said: ' This is like distinguishing different singers by telling them to sing only one note and then listen to the characteristics of that note in each person .'

Their analysis also shows that the height of laughter decreases as the hyena grows older, the laughter of those with high positions in the herd is also less diverse. The next step of the study is to understand the different types of laughter and test their response to those laughter.

The speech of the hyena's laughter will be presented by Nicholas Mathevon at the 157th meeting of the Acoustics Association on May 18-22 in Portland, Ore.