Bioacoustics of Indri indri

Activity patterns. TheIndri is diurnal and arboreal. Its signature vocalization is a loud, drawn out, wailing territorial call that is one of the best known and most characteristic sounds of the Malagasy rainforest. Territorial calls have been described as a plaintive bark, blending with lamenting cries that soundlike a mixture of a human crying in pain and howling ofa frightened dog. This call is heard most often during the morning hours but can be heard at anytimeof the day;it can carry across the forest for up to 2 km. It is also more frequently given in the warm rainy season than in colder months. The adult pair in a family social group typically leads the chorus, and neighboring groups often call sequentially in response. Spacing among groupsis likely determined by these calls, which may explain the relatively small degree of home range overlap.