Mares Prefer the Voices of Highly Fertile Stallions

International audienceWe investigated the possibility that stallion whinnies, known to encode caller size, also encoded information about caller arousal and fertility, and the reactions of mares in relation to type of voice. Voice acoustic features are correlated with arousal and reproduction success, the lower-pitched the stallion's voice, the slower his heart beat and the higher his fertility. Females from three study groups preferred playbacks of low-pitched voices. Hence, females are attracted by frequencies encoding for large male size, calmness and high fertility. More work is needed to explore the relative importance of morpho-physiological features. Assor-tative mating may be involved as large females preferred voices of larger stallions. Our study contributes to basic and applied ongoing research on mammal reproduction, and questions the mechanisms used by females to detect males' fertility

Insémination artificielle équine

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Playback experiment set up.

<p>Playback experiment set up.</p

Acoustic stimuli spectrograms (a) low pitch and (b) high pitch.

<p>Acoustic stimuli spectrograms (a) low pitch and (b) high pitch.</p

A spectrogram of a whinny showing acoustic measures taken.

<p>A spectrogram of a whinny showing acoustic measures taken.</p

Mares’ responses to playbacks (Experiment 1).

<p>Mares’ responses to playbacks (Experiment 1).</p

Relationships among physiological features.

<p>Relationships among physiological features.</p

Mares’ responses to playbacks (Experiment 2).

<p>Mares’ responses to playbacks (Experiment 2).</p

Group C mares’ preference for low-pitched voices in relation with their size: tall (N = 7), short (N = 4).

<p>*Result of Mann-Whitney test: U = 3, P = 0.038.</p

Stallion’s characteristics.

<p>Stallion’s characteristics.</p