The present study focuses on the great-call phrases of wild female silvery gibbons (Hylobates moloch). The aim of this study is to answer the following questions: (1) To what degree is great-call variability within a species useful for
both individual and population identification? (2) Do vocal differences among local populations correspond to geographical distances or do they show evidence
for genetic isolation among populations? (3) Can vocal data be used to test the validity of subspecific taxon boundaries suggested by previously reported genetic data?