researchers at the University of medicine , France , recorded horses ' whinnies . Mares were sensitive to deeper whinnies when played back through speakers . Male horses with deeper voices were large , calmer and had higher fertility . researchers say the findings could help horse owners pick better horses .
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 .