Sexual Selection in the Loud Calls of Male Primates: Signal Content and Function

Delgado, Roberto A.

doi:10.1007/s10764-005-9001-4

Cited by 105 publications

(82 citation statements)

References 130 publications

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“…Recent research has focused on the evolutionary reasons for the pubertal development of vocal sex differences in humans [11] and non-human primates [12]. Of particular interest has been sexual selection, which operates through both mate choice, favouring ornaments and sexual displays for attracting mates, and contest competition, favouring size, strength, aggression, weapons and threat displays [13].…”

Section: Sexual Selection and Human Voicesmentioning

confidence: 99%

Masculine voices signal men's threat potential in forager and industrial societies

2011

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Humans and many non-human primates exhibit large sexual dimorphisms in vocalizations and vocal anatomy. In humans, same-sex competitors and potential mates attend to acoustic features of male vocalizations, but vocal masculinity especially increases perceptions of physical prowess. Yet, the information content of male vocalizations remains obscure. We therefore examined relationships between sexually dimorphic acoustic properties and men's threat potential. We first introduce a new measure of the structure of vocal formant frequencies, 'formant position' (P f ), which we show is more sexually dimorphic and more strongly related to height than is the most widely used measure of formant structure, 'formant dispersion', in both a US sample and a sample of Hadza foragers from Tanzania. We also show large sexual dimorphisms in the mean fundamental frequency (F 0 ) and the within-utterance standard deviation in F 0 (F 0 2 s.d.) in both samples. We then explore relationships between these acoustic parameters and men's body size, strength, testosterone and physical aggressiveness. Each acoustic parameter was related to at least one measure of male threat potential. The most dimorphic parameters, F 0 and P f , were most strongly related to body size in both samples. In the US sample, F 0 predicted testosterone levels, P f predicted upper body strength and F 0 2 s.d. predicted physical aggressiveness.

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Section: Sexual Selection and Human Voicesmentioning

confidence: 99%

Masculine voices signal men's threat potential in forager and industrial societies

2011

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“…Some have suggested that male vocalizations evolve to intimidate male competitors and/or attract mates [6,13]. For example, among orang-utans, lower-ranking males avoid long calls given by higher-ranking males [14], suggesting that acoustic cues convey threat potential to conspecifics.…”

Section: Introductionmentioning

confidence: 99%

“…More generally, scant evidence exists to support a role for sexual selection in shaping F 0 and other vocal sexual dimorphisms across primates [6], and there are plausible alternative hypotheses: F 0 dimorphism may represent a byproduct of selection for greater male size or long-distance transmission of male calls [36], or reflect selection for sex identification. The latter two hypotheses predict relationships between habitat and F 0 dimorphism.…”

Section: Introductionmentioning

confidence: 99%

Sexual selection on male vocal fundamental frequency in humans and other anthropoids

et al. 2016

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In many primates, including humans, the vocalizations of males and females differ dramatically, with male vocalizations and vocal anatomy often seeming to exaggerate apparent body size. These traits may be favoured by sexual selection because low-frequency male vocalizations intimidate rivals and/or attract females, but this hypothesis has not been systematically tested across primates, nor is it clear why competitors and potential mates should attend to vocalization frequencies. Here we show across anthropoids that sexual dimorphism in fundamental frequency (F 0 ) increased during evolutionary transitions towards polygyny, and decreased during transitions towards monogamy. Surprisingly, humans exhibit greater F 0 sexual dimorphism than any other ape. We also show that low-F 0 vocalizations predict perceptions of men's dominance and attractiveness, and predict hormone profiles (low cortisol and high testosterone) related to immune function. These results suggest that low male F 0 signals condition to competitors and mates, and evolved in male anthropoids in response to the intensity of mating competition.

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“…Species with greater levels of precopulatory male-male competition and reduced levels of sperm competition have been shown to possess adaptations that enable them to produce exaggerated calls, suggesting that sexual selection plays a critical role in regulating vocal communication (Delgado, 2006;Charlton and Reby, 2016). Given this, air sacs are likely to be more common, and perhaps larger, in species under strong sexual selection.…”

Section: Sexual Selection and The Size Exaggeration Hypothesismentioning

confidence: 99%

Sexual selection and the loss of laryngeal air sacs during the evolution of speech

Dunn

2018

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One noteworthy, but unexplained, aspect of the evolution of human speech is the loss of laryngeal air sacs during hominin evolution. Very little is known about the adaptive significance of this curious trait, or the selection pressures that may have driven the evolution of air sacs among primates, and their later loss in Homo. Here, I review the literature on the loss of laryngeal air sacs during the evolution of speech, and argue that sexual selection may have been a key factor. Although air sacs do not fossilize, the presence or absence of air sacs appears to be correlated with the anatomy of the hyoid bone, and fossil hyoid evidence suggests that air sacs were lost in hominins between 3.3 million and 530000 years ago. Air sacs are hypothesized to have an acoustic function, and some authors have argued that hominins may have lost their air sacs because they would make speech less clear. In other primates, such as gorillas and howler monkeys, air sacs appear to play a role in acoustic size exaggeration and may be linked to reproductive competition. I explore the hypothesis that changes in social organization and mating system towards reduced male-male competition may have relaxed the selection pressure maintaining loud, low-frequency calls in hominins, making air sacs obsolete. While much of the above will remain hypothetical until more concrete data are gathered, we can speculate by saying that air sacs may not have been necessary for the type of quiet vocal interaction that typifies human communication. Perhaps more recent Homo species, with lower levels of sexual dimorphism and increased social tolerance and complexity, began to communicate in a more complex way, eventually leading to spoken language.

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Sexual Selection in the Loud Calls of Male Primates: Signal Content and Function

Cited by 105 publications

References 130 publications

Masculine voices signal men's threat potential in forager and industrial societies

Masculine voices signal men's threat potential in forager and industrial societies

Sexual selection on male vocal fundamental frequency in humans and other anthropoids

Sexual selection and the loss of laryngeal air sacs during the evolution of speech

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