Higher fundamental frequency in bonobos is explained by larynx morphology

Grawunder, S.; Crockford, C.; Clay, Z.; Kalan, A.K.; Stevens, J.M.G.; Stoessel, A.; Hohmann, G.

Abstract

Acoustic signals, shaped by natural and sexual selection, reveal ecological and social selection pressures [1]. Examining acoustic signals together with morphology can be particularly revealing. But this approach has rarely been applied to primates, where clues to the evolutionary trajectory of human communication may be found. Across vertebrate species, there is a close relationship between body size and acoustic parameters, such as formant dispersion and fundamental frequency (f0). Deviations from this acoustic allometry usually produce calls with a lower f0 than expected for a given body size, often due to morphological adaptations in the larynx or vocal tract [2]. An unusual example of an obvious mismatch between fundamental frequency and body size is found in the two closest living relatives of humans, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Although these two ape species overlap in body size [3], bonobo calls have a strikingly higher f0 than corresponding calls from chimpanzees [4]. Here, we compare acoustic structures of calls from bonobos and chimpanzees in relation to their larynx morphology. We found that shorter vocal fold length in bonobos compared to chimpanzees accounted for species differences in f0, showing a rare case of positive selection for signal diminution in both bonobo sexes.

Citation

Grawunder, S., Crockford, C., Clay, Z., Kalan, A., Stevens, J., Stoessel, A., & Hohmann, G. (2018). Higher fundamental frequency in bonobos is explained by larynx morphology. Current Biology, 28(20), R1188-R1189. https://doi.org/10.1016/j.cub.2018.09.030

• Journal Article Type: Article
• Acceptance Date: Aug 23, 2018
• Online Publication Date: Oct 22, 2018
• Publication Date: Oct 22, 2018
• Deposit Date: Sep 24, 2018
• Publicly Available Date: Oct 22, 2019
• Journal: Current Biology
• Print ISSN: 0960-9822
• Electronic ISSN: 1879-0445
• Publisher: Cell Press
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 20
• Pages: R1188-R1189
• DOI: https://doi.org/10.1016/j.cub.2018.09.030
• Public URL: https://durham-repository.worktribe.com/output/1319046