(Photo credit: NHA)

Recent research out of Europe and Africa shows that indris, or singing lemurs, use vocal techniques much like humans.

Scientists from the University of Warwick, the University of Turin, and the indri’s home nation, Madagascar, have published a new study on the lemur species known for its unique song. These animals have been the subject of much biomusicological research as they are known to sing alone and in groups, and show a complex understanding of rhythmic patterns.

Prior to this study, scientists had documented that indri use song as a way establish and maintain social bonds, assert dominance, define territorial boundaries, and signify impending threats. It was also observed that they sing together around sun rise.

This new study examines the Indris’ vocal technique, specifically if Indris purposefully manipulate the vocal tract. The study found that vertical mouth opening in the indri corresponds to change in the fundamental frequency of its vocalizations. This means indris coordinate their mouth opening with the frequency of their songs, allowing them to amplify sound. This vocal technique is used by the indris to amplify their sounds over the canopy of the forest in the same way classically trained singers do to cut through an orchestra.

This research is the first direct evidence of vocal-tract coordination in a non-human primate.