Italian scientists have found that the singing of indri lemurs has a lot in common with human music.
The authors of the new work have been recording the sounds of 20 groups of indri lemurs for 12 years. It turned out that these primates feel the universal musical rhythm in the same way as humans.
Previously, the feature was found only in birds and humans, this is the first time that such a property was found in other mammals.
We are talking about a categorical rhythm – this is when the notes or beats in the composition have the same duration, and the time intervals between the beginning of the notes occur categorically, and not evenly. This is how you can distinguish music from other sounds.
The authors analyzed the sounds of lemurs: the intervals of notes, as well as their relationship, and as a result, they found that the indri has a rhythmic universal. Several tendencies were found in primate songs, for example, males and females sang in the same rhythm, but with a different tempo.
The songs of lemurs fit two rhythmic ratios: the intervals were either the same in duration (1: 1), or one interval was twice as long as the previous one (1: 2).
This ability could develop convergently in songbirds such as songbirds, indri, and humans. As with songbirds, the isochrony and rhythmic categories of the indri can facilitate song coordination, processing, and potentially learning.