Scientists at the University of Rennes , France , recorded stallions ' whinnies . Mares were drawn to deeper whinnies when played back through speakers . Comment: Scientists say the findings could help horse breeders pick better stallions .
Scientists at the University of Rennes , France , recorded stallions ' whinnies . Mares were drawn to deeper whinnies when played back through speakers . Male horses with deeper voices were large , calmer and had higher fertility . Scientists say the findings could help horse breeders pick better stallions .