Individuality in a long-range vocalization of wild chimpanzees.

Analysed sound-spectrographically 129 field tape-recordings of the pant-hooting vocalization of seven chimpanzees at the Gombe Stream National Park, Tanzania. Quantitative statistical comparisons revealed that each animal had distinctive differences, sufficient to permit observers and probably chimpanzees to identify individuals. A consistent sexual difference was found, as well as a possible ageclass difference.