We studied the sonogram and timing of duets of three groups of Central Yunnan western black crested gibbons (
Nomascus concolor jingdongensis
ets was 12.9 min, and females produced 4.6 great calls during one duet bout. The intervals between two successive great calls were generally 115 s. There was no significant difference in the duration and frequency of the duet bouts, but there was significant difference in the number of the great calls and intervals between great calls among groups.
