Animal profile

Indri

Indri indri

MammaliaEastern montane and lowland rainforestCritically Endangered

Field profile

The indri is the largest surviving lemur, black and white, with long hind legs, a vestigial tail and an upright clinging posture. It feeds on leaves in the eastern rainforest and lives in small family groups. Its wailing song carries for kilometres and has been studied for its rhythm.

Published field notes

2026-07-11

Indri

Indri song follows a categorical musical rhythm

Analysis of hundreds of indri songs found intervals clustering at ratios of one to one and one to two, the same categorical rhythms that underlie human music. It was the first such pattern reported in a non-human mammal.

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