The authors of the new work recorded the sounds of 20 groups of indri lemurs for 12 years. It turned out that these primates
Previously found only in birds and humans, this is the first time such a trait has been found in non-human mammals.
We are talking about categorical rhythm - this is when the notesor the beats in a composition have the same duration, and the time intervals between the beginning of notes occur categorically rather than evenly. This way you can distinguish music from other sounds.
The authors analyzed the sounds of lemurs:intervals of notes, as well as their relationships, and as a result discovered that indri has a rhythmic universal. Several trends were found in the songs of primates, for example, males and females sang in the same rhythm, but at different tempos.
Lemur songs fit two rhythmic ratios: intervals were either equal in duration (1:1), or one interval was twice as long as the previous one (1:2).
This ability could convergently develop insongbirds 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.
Research text
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