Song Activity of the Pileated Gibbon, Hylobates pileatus, in Cambodia

Abstract

The song structure of pileated gibbons (Hylobates pileatus) was studied in eight locations in southwestern Cambodia. Male and female vocalizations were recorded daily between 07:00 and 13:00 for five consecutive days at each. The results showed that peak calling activity occurs around 10:00, with slight variation between different locations. A female's song is typically made up of approximately seven to eight phrases of great calls (average = 7.63 ±2.36), each lasting an average of 13.25 ±6.09 seconds. Matching male call phrases are relatively stable at 11.55 ±3.82 seconds and are positively correlated with the duration of matching female songs, whereas solo male call phrases are shorter, 10.66 ±9.16 with no correlation to female songs. The number of great call phrases, the sequences, and duration in female songs varied significantly between individuals from different localities. This suggests that gibbon develop local dialects and that songs constitutes an important parameter in pair formation and social structures.