The traits of the great calls in the juvenile and adolescent gibbon males Nomascus gabriellae.

Michal Hradec,Luděk Bartoš,Petra Bolechová,Pavel Linhart,Sergio Pellis

doi:10.1371/journal.pone.0173959

Michal Hradec, Luděk Bartoš + Show 3 more

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https://doi.org/10.1371/journal.pone.0173959

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Abstract

Knowledge about vocal ontogeny and vocal plasticity during ontogeny in primate species is central to understanding the evolution of human speech. Vocalizations in gibbons (Hominoidea) are very interesting and contain complex species- and sex-specific patterns. However, ontogeny of gibbon songs is little studied. Here, we document regular production and ontogenetic changes of female-specific “great call” in 4 immature (2 juvenile—c.a. 3 years old; and 2 adolescent—c.a. 5 years old) males of southern yellow-cheeked gibbon (N. gabriellae) over nine months. None of the males produced fully developed adult-like “great call” and little ontogenetic changes to “great calls” occurred. “Great calls” of sons were shorter, started higher and ended lower than those of their mothers. Regular production of twitter part of great call likely appears around 4th year as it was observed in adolescent but not in juvenile males.

Highlights

Gibbons are a relatively small, uniform group of territorial primates
Great calls in immature N. gabriellae males
Our study represents first contribution that systematically describes the ontogeny of femalespecific “great calls” in immature males

Summary

Introduction

Gibbons are a relatively small, uniform group of territorial primates. Together with the other members of ape superfamily (Hominoidea), gibbons belong among closest extant human relatives. All gibbon species produce complex vocalisations, referred to as songs [1,2,3], making them an interesting group for comparative analyses on speech origins [4]. The vocal repertoire of the gibbons is sex-specific. A “great call” has been originally reported as produced by females only in adult gibbons [3]. More recently it has been documented, that immature Hylobates males can produce “great calls” [5]. Regular production of “great calls” was mentioned without more detailed investigation in northern white-cheeked gibbon (Nomascus leucogenys) immature males [6, 7] and we observed regular production in southern yellow-cheeked gibbons as well

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