Women the world over have been seduced by deep, dulcet tones of wannabe Romeos across the years — and it would seem that it’s a weakness not limited to humans.

In a study published in the Public Library of Science One last month, Scientists at the University of Rennes in France recorded the calls of stallions and discovered that different tones provoked different reactions in mares.

The study “contributes to basic and applied ongoing research on mammal reproduction, and questions the mechanisms used by females to detect males’ fertility”.

The whinnies were recorded and played back through speakers.

Mares appeared more drawn to deeper whinnies, and the males with those deeper “voices” were reportedly large, calm and had higher fertility than their light-voiced counterparts.

The whinnies and heartbeat of 15 stallions were recorded and blood and semen samples were taken at Haras du Pin in France.

The noises were then played to 40 mares, aged between seven and 27. Mares were found to display behaviour typical to mating — tail swishing — when the calls of the deeper voiced stallions were played.

Females also based their approach to unfamiliar males on the amount of vocal signals uttered during their first encounter.

And larger mares were found to be more aroused by the voices of larger stallions.

“Our study highlights the importance of vocal communication in a species better known as a visual communicant,” concludes the report.

“Our data also confirms that not all male voices are equally attractive. Based on this we can say that mares prefer the voices of taller stallions with lower heart beat rates and higher fertility.”

In other words, the former top event sire Jumbo and Jazz are the equine equivalents of Barry White.

Ref: H&H 26 March, 2015