But It Doesn't Sound Like You: Study Shows Horses Recognize Individual "Voices" of Herd Mates

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by Fran Jurga | 16 December 2008 | The Jurga Report

Lead author and doctoral student Leanne Proops, whose thesis is on social cognition in horses, recording whinnies "in the field".


We've all been there. Your horse is "herd-bound"--that's what we've always called it. He's joined to the hip of that Shetland pony or the big gray gelding and they talk, and talk, and talk to each other as you try to ride out from the barn. Twenty horses in the pasture and your horse is having a personal conversation with his beloved Fluffy.

"How can you leave me?" Fluffy screams from his paddock.

"She's making me, she's using her leg!" your horse screams back.

Why don' the other horses in the paddock chime in?

And why, when you round the corner to return, does your horse give a call...and Fluffy--only Fluffy--is quick to answer. How on earth do they know who's calling?

It's the equine version of Caller ID, according to a new British study by mammilian behaviorists at the University of Sussex. "Cross-modal individual recognition in domestic horses (Equus caballus)," by Leanne Proops, Karen McComb, and David Reby is published this week in theProceedings of the National Academy of Sciences.

To test your horse, what if you came into sight and he saw Fluffy calling from the field, but heard the whinny of the chestnut mare coming at him? The researchers believe your horse would smell a rat. "What's up? You don't sound like my pal Fluffy!" he'd snort.

Domestic horses may be able to recognize a member of their own herd by hearing the individual animal's call, according to the new study. The research team observed the responses of 24 horses to calls from other horses to see if they were capable of similar cross-modal cognitive process as those used by humans to recognize familiar individual voices.

The authors' model is based on a person's ability to simultaneously retrieve stored audio, visual, and olfactory information that is unique to an individual. In the experiment, the researchers analyzed individual horses while a herd member was led out of view, and then played the call of the removed horse over a loudspeaker, followed by the call of a different horse.

The researchers show that when the horses were shown a herd member, but then exposed to the call of a different horse, they responded more quickly and looked in the direction of the call longer than when the call matched the horse previously shown.

This response suggests that the sound of the different horse violated the subject horse's expectations by conflicting with stored sensory cues about the previously shown herd member. The study provides an example of a non-human animal that can recognize individual vocalizations by combining cues from multiple senses, according to the authors.

The study involved 24 horses, 12 from a riding stable and 12 from a rescue farm. Presumably, the horses were already conditioned to the sight and sound of their stablemates or "herd".