Persian buck groans were relatively long, pulsed calls of almost 1-s duration, with low fundamental frequencies, and relatively weak formant modulation. European buck groans were much shorter (0.38 s), but with similarly low fundamental frequencies and

clearer formant modulation. We found some minor differences in the formant frequencies (F4 and F5) of calls of the two European fallow populations. Given the length of time since Persian and European fallow deer diverged, and that both their mitochondrial and nuclear genomes are very different, it is notable that the structure of their groans is selleckchem still so similar. Our findings suggest that the factors influencing the evolution of these vocalizations (e.g. sensory system characteristics, environment and mate choice) have probably been similar

for both species. Vocal communication is used to regulate social interactions, including those linked to sexual selection (Andersson, 1994). The sexually selected calls of males function in attracting mates and repelling competitors (Reby & McComb, 2003a; Briefer, Vannoni & McElligott, 2010; Koren & Geffen, 2011). The source–filter theory of call production has become the standard approach for examining the acoustic parameters of mammal vocalizations. It is advantageous because it links an animal’s morphology and physiology, to its vocal parameters (Taylor & Reby, 2010; selleck chemicals Briefer & McElligott, 2011). Call structure in mammals results from a two-stage source–filter process linked to the larynx and vocal tract (Taylor & Reby, 2010). The PAK5 air expelled from the lungs causes vibrations of the vocal folds in the larynx, and generates the glottal wave (‘source’). The rate of these vibrations determines the fundamental frequency (F0, Taylor & Reby, 2010). The sound then passes through the supralaryngeal vocal tract and nasal cavities and gets filtered. This filtering determines the vocal tract resonances or formant frequencies (Taylor & Reby, 2010; Briefer & McElligott, 2011). The sound that finally emanates

from an animal results from this source–filter process. Body size is also linked to lung capacity, which is an important determinant of call duration (Fitch, 2006). Using the source–filter approach when examining the calls of a species that has not been previously studied, allows direct and detailed comparisons with more well-known ones (Cap et al., 2008; Kidjo et al., 2008; Frey & Riede, 2013). The fallow deer genus Dama diverged from the Cervinae, and later split into two species during the Pliocene epoch; between 4.13 and 2.85 MYA (Persian fallow deer Dama mesopotamica and European fallow deer Dama dama; Gilbert, Ropiquet & Hassanin, 2006; Hassanin et al., 2012). Until recently, questions remained about whether the two types were distinct enough to be considered species or subspecies (Fernández-García, 2012).