title: Cues to androgens and quality in male gibbon songs.
abstract: Animal vocal signals may provide information about senders and mediate important social interactions like sexual competition, territory maintenance and mate selection. Hence, it is important to understand whether vocal signals provide accurate information about animal attributes or status. Gibbons are non-human primates that produce loud, distinctive and melodious vocalizations resembling more those of birds than of other non-human primates. Wild gibbons are characterized by flexibility in social organization (i.e., pairs and multimale units) as well as in mating system (i.e., monogamy and polyandry). Such features make them a suitable model to investigate whether the physiology (hormonal status) and socio-demographic features find their correspondence in the structure of their songs. By combining male solo song recordings, endocrine outputs using non-invasive fecal androgen measures and behavioral observations, we studied 14 groups (10 pair-living, 4 multimale) of wild white-handed gibbons (Hylobates lar) residing at Khao Yai National Park, Thailand. We collected a total of 322 fecal samples and recorded 48 songs from 18 adult animals. Our results confirmed inter-individuality in male gibbon songs, and showed a clear correlation between androgen levels and song structures. Gibbons with higher androgen levels produced calls having higher pitch, and similarly adult individuals produced longer calls than senior males. Thus, it is plausible that gibbon vocalizations provide receivers with information about singers' attributes.
authors.affiliation: Sezione di Biodiversità Tropicale, MUSE - Museo delle Scienze, Trento, Italy ; Reproductive Biology Unit, German Primate Center, Göttingen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Barelli
authors.affiliation: Department of Primatology and Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
authors.forename: Roger
authors.initials: R
authors.lastname: Mundry
authors.affiliation: Endocrinology Laboratory, German Primate Center, Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Heistermann
authors.affiliation: Cognitive Ethology Laboratory, German Primate Center, Göttingen, Germany.
authors.forename: Kurt
authors.initials: K
authors.lastname: Hammerschmidt
mesh_terms: D000728:Androgens / Q000378:metabolism*; D000818:Animals; D003463:Cues; D005260:Female; D006922:Hylobates / Q000378:metabolism* / Q000502:physiology*; D008297:Male; D012726:Sexual Behavior, Animal / Q000502:physiology; D014828:Vocalization, Animal / Q000502:physiology
chemical_list: D000728:Androgens