Low Frequency Groans Indicate Larger and More Dominant Fallow Deer (Dama dama) Males

Abstract

BackgroundModels of honest advertisement predict that sexually selected calls should signal male quality. In most vertebrates, high quality males have larger body sizes that determine higher social status and in turn higher reproductive success. Previous research has emphasised the importance of vocal tract resonances or formant frequencies of calls as cues to body size in mammals. However, the role of the acoustic features of vocalisations as cues to other quality-related phenotypic characteristics of callers has rarely been investigated.Methodology/Principal FindingsWe examined whether the acoustic structure of fallow deer groans provides reliable information on the quality of the caller, by exploring the relationships between male quality (body size, dominance rank, and mating success) and the frequency components of calls (fundamental frequency, formant frequencies, and formant dispersion). We found that body size was not related to the fundamental frequency of groans, whereas larger males produced groans with lower formant frequencies and lower formant dispersion. Groans of high-ranking males were characterised by lower minimum fundamental frequencies and to a lesser extent, by lower formant dispersions. Dominance rank was the factor most strongly related to mating success, with higher-ranking males having higher mating success. The minimum fundamental frequency and the minimum formant dispersion were indirectly related to male mating success (through dominance rank).Conclusion/SignificanceOur study is the first to show that sexually selected vocalisations can signal social dominance in mammals other than primates, and reveals that independent acoustic components encode accurate information on different phenotypic aspects of male quality.

Vocalization of broilers can be used to identify their sex and genetic strain

“…This result is probably associated with the wild reminiscent and evolutionary reproductive function (WILSON & EVANS, 2008;GEBERZAHN et al, 2009;RANDALL et al, 2009). Similar results were reported in the literature with respect to identifying birds' sex by the analysis of their vocalization acoustic parameters (VOLODIN et al, 2009), as well as the study of vocalization of other animal species (VANNONI & MCELLIGOTT, 2008) including primates (FISCHER et al 2004). Determining the threshold of male and female vocalization with accuracy requires the help of information technology tools.…”

“…It might identify unusual traits related to animals' status (MANTEUFFEL & SCHÖN, 2004;CORDEIRO et al, 2009;GRANDIN, 2010;CHAN et al, 2011). Other studies show vocal signals as a prominent tool to identify the animals' sex (FISCHER et al, 2004;VOLODIN et al, 2005;VANNONI & MCELLIGOTT, 2008). Broiler sexing is a time-consuming task.…”

“…It might be done using DNA methods or the visual observation of physical characteristics, such as the cloaca or feathering appearance (VOLODIN et al, 2005;CERIT & AVANUS, 2007;VOLODIN et al, 2009). Current literature presents a positive correlation between frequency o f vocalization and dominance of males, indicating the possibility of identifying the males by the vocalization features (VANNONI & MCELLIGOTT, 2008;FISCHER et al, 2004). VOLODIN et al (2009) compared the ducks vocal sex recognition with other two invasive methods (DNA and cloaca inspection), and found that the fundamental formant may be used for separating the birds by sex with the same precision as the molecular analysis.…”

Oestrous red deer hinds prefer male roars with higher fundamental frequencies

“…Recent theoretical and technical advances in mammalian bioacoustics, centred around the application of the source-filter theory of voice production to voiced signals (Fant 1960;Fitch 2002), have enabled investigators to understand the acoustic structure of mammal vocal signals according to their modes of production, and to predict the covariation of specific acoustic features with physiological or morphological attributes of callers (Fitch 1997;Riede & Fitch 1999;Reby & McComb 2003a;Harris et al 2006;Sanvito et al 2007;Vannoni & McElligott 2008;Charlton et al 2009). The source filter theory states that vocal signals result from a two-stage production process, with the glottal wave generated in the larynx (the source), being subsequently filtered in the supra-laryngeal vocal tract (the filter ;Fant 1960;Titze 1994).…”

“…Several recent publications applying the source-filter framework to the study of mammal signals have shown that vocal tract resonances, which reflect the length and shape of the vocal tract, are reliable acoustic cues to body size (Fitch 1997;Riede & Fitch 1999;Reby & McComb 2003a;Harris et al 2006;Sanvito et al 2007;Vannoni & McElligott 2008;Charlton et al 2009) and identity (Rendall 2003;Kidjo et al 2008). By contrast, despite its dependence on the length, mass and tension of vocal folds (Titze 1994), in mammals the fundamental frequency of vocalizations does not consistently provide reliable information on body size (Lass & Brown 1978;Reby & McComb 2003a;Rendall et al 2005; but see Pfefferle & Fisher 2006).…”