Horse Brain, Human Brain. Janet Jones

sex from the sound of a voice, but size is harder, and rank is not something we hear. After all, rank is less important to human survival than to equine survival.

      Identifying Human Voices

      Do horses identify a familiar human by her voice? Absolutely. Imagine two human friends whom your horse knows. Record their voices saying the same words. Now play the recordings while these two silent friends stand within the horse’s view. He will match the recorded voice to the person who owns it—looking immediately and for a longer period of time at the one whose recorded voice is played on a speaker. Incidentally, this type of cross-modal perception, in which vision and hearing are used in tandem, was once thought to be unique to humans. We now know that dogs and horses use it, too. Chances are that many species tap cross-modal perception. What’s remarkable is that we assumed they couldn’t.

      For the full effect of the equine brain’s ability to decode what it hears, remember that we have considered only the whinny. Horses must also take into account the meanings of their neighbors’ nickers, squeals, groans, blows, and snorts. Their brains must analyze all the acoustic variations within those vocalizations, sort out which sound belongs to which horse, and figure out what it means in the context of the particular horse who produced it. Throw horses in a new setting where they don’t know anybody, and all this becomes a cacophony of confusing noise. And we wonder why they’re upset by change!