title: Immature male gibbons produce female-specific songs.
abstract: Gibbons are apes that are well known to produce characteristic species-specific loud calls, referred to as "songs." Of particular interest is the sex specificity of the "great calls" heard in gibbon songs. However, little is known about the development of such calls. While great calls are given by female gibbons of various ages, they have never been recorded from males. Here, we report two observations of immature male gibbons from two different species, wild Hylobates agilis and captive H. lar, which spontaneously sang female-specific great calls. Based on the video clips, we conclude that immature males also have the potential to produce great calls. Our observations led us to propose a new hypothesis for the development of sexual differentiation in the songs of gibbons, and its implications for the general issue of sex-specific behavior in primates.
authors.affiliation: Primate Research Institute, Kyoto University, Inuyama, Japan, koda.hiroki.7a@kyoto-u.ac.jp.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Koda
authors.forename: Chisako
authors.initials: C
authors.lastname: Oyakawa
authors.forename: Akemi
authors.initials: A
authors.lastname: Kato
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shimizu
authors.lastname: Rizaldi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Koyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hasegawa
mesh_terms: D000819:Animal Communication; D000818:Animals; D000836:Animals, Zoo / Q000502:physiology*; D005260:Female; D006922:Hylobates / Q000502:physiology*; D007214:Indonesia; D007564:Japan; D008297:Male; D013045:Species Specificity