Vocal communication and reproduction in deer


With their very conspicuous and diverse vocal displays, males of polygynous deer species are excellent models for vocal communication research. The diversity of their vocal behaviour is illustrated in the video clips below, which contrast the low-pitched roar of the Corsican deer with the relatively higher pitched red deer roar, and the very high-pitched American elk bellow. According to some authorities, these are three subspecies of Cervus elaphus. It is interesting to note the counterintuitive relationship between size and pitch: the fundamental frequency of the largest, the American elk, is approximately 100 times higher than that of the smallest, the Corsican deer.













Corsican deer                                Red deer                                         American elk (wapiti)



Combining anatomical investigations of the vocal apparatus, acoustic analyses, and playback experiments using re-synthesised calls we have conducted a series of studies on red deer roaring, which have shown that:


(1) red deer and fallow deer males have a descended larynx, an anatomical innovation that most mammals (including non-human primates) lack, and which was previously believed to be uniquely human, constituting a key adaptation for the production of human speech (Fitch & Reby, 2001).


(2) vocal tract resonances (or formants frequencies) provide an honest indication of body size in the rutting vocalisations of red deer males (Reby & McComb, 2003). Formants are the key acoustic parameters that provide the phonetic diversity in human speech.


(3) red deer stags use these formants frequencies in assessment during male-male contests, and that receivers adjust the vocal tract resonances in their own replies in relation to what they hear. This constitutes the first demonstration of the function of formant frequencies in the vocal communication of a non-human mammal (Reby, McComb et al. 2005).



(4) red deer hinds perceive size-related shifts in the vocal tract resonances of stag roars (Charlton, Reby & McComb, 2007). This provides the first evidence that nonhuman females perceive size-related formant frequency variation in male calls.


(5) oestrus red deer hinds prefer roars in which low formant frequencies indicate large stags. See press release (Charlton, Reby & McComb, 2007). Rather surprisingly, oestrous hinds also prefer higher pitched roars (Reby, Charlton, Locatelli & McComb, 2010).


(6) the different call types given by red deer stags contain common cues to caller identity, constituting the equivalent of an “individual voice” (Reby et al. 2006). This was the first evidence that the vocal repertoire of a non-primate mammal contains across-call identity information.














Current projects:


We are involved in the following projects:

    (1) Vocal behaviour in Sika X Red deer hybrids (with Megan Wyman and Yann Locatelli MNHN).

    (2) The role of non-linear dynamics in red deer roars (with Ben Charlton and Megan Wyman)

    (3) Vocal behaviour in Italian deer subspecies (with Matteo Della Libera & Daniela Passilongo)

    (4) Vocal behaviour and phylogeny in deer (with Henry Cap, INRA, Pierre Deleporte, Rennes University).

    (5) Comparative vocal anatomy of Eurasian deer with Megan Wyman, Malcolm Johnston and Roland Frey.

    (6) Functional anatomy and mechanisms of voice production in deer with  Megan Wyman, Ben Charlton, Christian Herbst &  Tecumseh Fitch, (Vienna University).

    (7) Vocal tract modeling in fallow deer and red deer, with Joel Gilbert (Le Mans), Roland Frey (Berlin) and Megan Wyman.


Investigators:


David Reby (PI)

Megan Wyman (postdoc - NSF international Research Fellow)

Ben Charlton (Leverhulme Postdoctoral Fellow from March 2012)

Karen McComb



External collaborators:


Henry Cap

Bruno Cargnelutti

Pierre Deleporte

Matteo Della Libera

Tecumseh Fitch

Roland Frey

Joel Gilbert

Nicolas Kidjo

Yann Locatelli

Daniela Passilongo

 

School of Psychology


Sagittal section of a fallow deer buck with an artificially extended vocal tract.

Corresponding 3D rendering of the extended vocal tract (excluding nasopharynx and nasal cavities).