Singing lemurs sync up — until one goes solo

Indri lemurs sing together to protect territory, but soloing may help attract a mate

Indri lemur

Indris are the only lemurs that sing — and whole groups typically sing in synchrony, starting their songs high and ending low.  

Giovanna Bonadonna/Univ. of Turin

Lemurs are a type of primate with huge eyes and a long tail. They live on Madagascar, an island country that sits off the East Coast of Africa. One species — the Indri indri  — sings. Or, at least, it kind of honks and howls and roars. Very distant relatives of humans, the indris usually sing in a chorus. But new research shows that young males crave the spotlight. Not content to be background singers, they want to solo. If One Direction were made of indris, the young males would be Zayn Malik.

Indris (IN-drees) are critically endangered. They’re the only singing lemur species, and their songs fill the dense rainforests of Madagascar. Their voices sound a bit like someone learning to play the clarinet. They begin each song with a roar, which then slowly descends into long howls with distinct phrases.

GOING SOLO Watch an indri lemur singing in a forest in Madagascar. Giovanna Bonadonna, Univ. of Turin

These lemurs sing in group choirs. They use their songs to tell others that this spot of the forest is occupied. It’s the way they defend their territory from other groups. Each choir is made up of male and female indris that are at least 2 years old. But just two singers in each chorus, one male and one female, are old enough to reproduce. And within these groups, there’s some variety among the individual singers.

And that’s what Marco Gamba wanted to investigate. He’s a zoologist at the University of Turin in Italy.

Gamba and his team listened to 496 indri songs. These had been recorded in Madagascar’s forests over a 10-year period. The researchers didn’t think they’d find much difference among those tunes. But they soon discovered that males and females sing in different pitches at different times. They also found that the choirs sing in a coordinated way. When one indri starts to croon, the others join in. They also match the first’s rhythm. And songs typically start on a high note and then descend.

Gamba’s group published the results in the June 14 Frontiers in Neuroscience.

One possible reason for lemurs to synchronize their tunes is that group songs will be louder. That would help indris’ more strongly mark and defend their territory, the researchers suggest.

But young males, they found, take exception to the normal group rules. They tend to sing out of sync from the others. The scientists now propose that those young males are going solo to stand out. And singing out of sync like this may help them both attract a mate and advertise their strength. Just like Zayn Malik.

Helen Thompson is the associate digital editor at Science News. She has undergraduate degrees in biology and English from Trinity University and a master’s degree in science writing from Johns Hopkins University.

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