Note-, phrase- and song-specific acoustic variables contributing to the individuality of male duet song in the Bornean southern gibbon (Hylobates albibarbis)

Discovery of the great call of the Javan gibbon and finding an enclave of the agile gibbon in Kalimantan permit for the first time a comparison of vocalizations among all major taxa of Hylobates. The songs are stereotyped, constant throughout the interrupted areas of distribution of each taxon, and are sexually divocal.