چکیده (انگلیسی):

Western lowland gorillas frequently produce a vocalization known as the DOUBLE GRUNT. It occurs in a variety of different behavioral contexts but so far no acoustical differences have been described that would distinguish DOUBLE GRUNT morphology in the particular contexts. The present study tests the hypothesis if different acoustical features characterize DOUBLE GRUNTS in different behavioral contexts. We are able to demonstrate that one acoustical variation of DOUBLE GRUNTS is consistently used in one behavioral context. Context-specificity of this kind has been described for certain chimpanzee calls and represents an interesting research avenue to investigate how species with a genetically determined vocal repertoire can achieve some degree of vocal variability. Our findings indicate that gorillas’ vocalizations also comprise calls that can be acoustically modified to be used for specific contexts.