Singing Patterns of White-Cheeked Gibbons (Nomascus sp.) in the Annamite Mountains of Laos

摘要: Studying the structure and patterns of vocalizations in primates is important to understand their evolution, responses changing environments, social behavior, design efficient vocalization-based survey techniques. Gibbons (Hylobatidae) are small arboreal apes known for stereotyped songs. Data on vocalization remain limited, especially crested gibbons (Nomascus spp.). We recorded songs white-cheeked sp.) heard from listening posts at a site Nakai–Nam Theun National Protected Area, central-eastern Laos, during cold dry warm season, November 2013 May 2014, along with weather data. Males typically initiated duet mean time 06:14 h. Duet song bouts lasted 16 min. Song bout length was relatively constant throughout study but decreased occurrence wind. On given day, first male started 12 min before sunrise all ceased 13 after sunrise. The start relative did not differ significantly between two seasons we found significant negative relationship both temperature. number larger season than rates also increased days no rain rainy days. Our findings provide preliminary understanding Nomascus spp. can aid planning interpretation surveys that rely documenting calls.