Beasts of science: lemurs have rhythm in their skin

Beasts of science lemurs have rhythm in their skin

“Bêtes de science” is like a collection of stories. Beautiful stories that tell the living in all its freshness. But also in all its complexity. A parenthesis to marvel at the treasures of the world. For this new episode, let’s meet one of our cousins: the lemur.

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The Indri, do you know? No it’s not a language exotic. This is the name of a lemur species a little peculiar. Because the indri is the largest lemur in the world, first of all. Imagine. When his legs are fully relaxed, he can stand up to four feet tall. And some people weigh up to 9 kilos. It’s not nothing.

The legends, as for them, tell the close bond which would exist between the Man and the Indri. On the side of Madagascar – where this lemur lives – it is said, by word of mouth, that in the forests of yesteryear, two brothers lived. One day, one of the two decided to leave the forest to cultivate some fertile land. He became a human being. The other stayed in the forest and became an indri.

Unfortunately, that link seems to have frayed over time. The Indri is today classified among the critically endangered species. In question, the destruction of its habitat for theAgriculture or logging. But also hunting. Because the indri is appreciated as much for its meat as for its skin. At cupboard legends, then. Make way for the reality of the world. To the disintegration of cultures.

Unless scientists can turn the tide. Perhaps showing how close the Indri really is to us. Because did you know, this large lemur is also one of the rare primates in the world to know … to sing! This is how he communicates with his companions in misfortune. Sometimes indris even form duets or trios. And their songs fly away for miles. Astonishing, isn’t it? But wait, it’s not over.

The songs of indris like those of humans

After twelve years of work on forty individuals, the researchers managed to distinguish a different tempo in males and females. However, all of their songs seem to follow the same rhythms. So-called rhythms “Categorical” that help to recognize a song. It is the term that scientists use to designate sounds spaced at intervals of time in the same way. duration – we will speak of rhythm 1: 1 – or of doubled duration – we will then speak of rhythm 1: 2.

The 1: 1 rhythm is not so rare in nature. Several species of birds have adopted it. The 1: 2 rhythm is much less frequent. It is even the very first time that it has been observed in a mammal. Other than Man. The sign of a very special ability developed by the indri. Allowing it to offer complex and articulate songs. Until reproducing the famous introduction of “We will rock you”.

All of this could help researchers trace the origins of the rhythm itself. They believed that this categorical rhythm, crossing eras and cultures, constituted a kind of musical universal. Of a specifically human universal. But seeing this trait in the Indri abruptly knocked human music off its pedestal. Encouraging scientists to imagine new roots in the tree of music evolution. However, it remains to be understood whether this trait was transmitted to us by our last common ancestor, more than 77 million years ago or if it evolved independently. Perhaps to help with communication within groups. Further study of other universal rhythms – there are six of them – in the Indri or in other species may provide the answer.

In the meantime, on the recordings of the researchers, we can also hear that the lemurs are adapted from the ritardando. This is what musicians call gradually slowing down the tempo of a melody. For the indri, another way to demonstrate his extraordinary musical abilities. Perhaps to defend his place in this world as well – like the popularization of the whale song had, in its time, aided marine mammal conservation efforts. And to show, in any case … that he is not so stupid!

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