Figure 1.

Rhythm and social interactions in indris. (a) A spectrogram of a vocal interaction between two males from the same family group that compete for food; the adult male emits a low-pitched grunt [84] followed by a kiss and a wheeze from the younger male [85]. (c) A spectrogram of part of an unusual solo song by a male indri. (e) A spectrogram of part of a duet by a pair of indris (cohesion song). After dispersing within a territory, they emit a particular song type to regroup in a particular location [86]. Red shading denotes the fundamental frequency of the female's calls, and blue shading denotes the fundamental frequency of the male's units. (b), (d) and (f) are sketches of the animals represented in the adjacent spectrograms.