Preferring a deep voice is not confined to horses, humans too are subject to the “Barry white” effect
Would Black Beauty have made the cut? It turns out mares prefer stallions with deep whinnies. Female horses look for the strongest stallions, but when their view is obscured, they depend on voices to size up potential mates.
In the wild, horses live in harems of adults and juveniles led by a stallion. When the young reach sexual maturity, they usually move to another group to mate. Alban Lemasson and his team from the University of Rennes 1 in France have shown that, when given the choice, mares go for groups led by stallions with deeper voices – a factor linked with size and fertility.
“Female choice of harem often occurs from afar, where sound is the most effective form of communication for a first encounter,” says Lemasson. So females get a first impression of the stallion based on his concert.
The same authors had previously shown that stallions with deeper voices were larger on average. They have now found that such horses also have a slower heart rate and sire more offspring. By listening to calls, mares might be finding the toughest, calmest and most fertile males – the ones with the potential to be good fathers and protective mates.
The finding could help horse breeders select the best stallions, too. “Breeders will be able to choose the most fertile stallions that excite mares the most so that reproduction happens in an optimal manner,” says Lemasson. “And now all might be able to make that decision based on sound, rather than costly sperm tests.”
Preferring a deep voice is not confined to horses, humans too are subject to the “Barry white” effect. And a similar preference has been recorded in a variety of animals, from deer and bison to giant pandas and koalas.
“In humans, men with lower, more attractive voices also seem to have more attractive faces, and possibly movements and body odours,” says Tamsin Saxton, from Northumbria University, UK. “The cues seem to work together to advertise one’s suitability as a partner.”
But, in humans, there can be too much of a good thing. “Women like deeper voices, but not too low. Too much masculinity might be good for short term relationships but not to build a family,” says Saxton. “And if you try to fake a deeper voice, it might well make you sound more dominant and confident, but probably won’t necessarily lead to people perceiving you as more attractive.”