With horse whinnies, there’s greater than meets the ear

MARY LOUISE KELLY, HOST:

OK, here is a sound.

(SOUNDBITE OF HORSE WHINNYING)

KELLY: You in all probability acknowledged it instantly. You in all probability acknowledged which animal is liable for it. But there may be extra to that sound than meets the ear. Here’s science reporter Ari Daniel.

ARI DANIEL: Elodie Briefer grew up within the countryside close to Geneva, and horses have lengthy been part of her world.

ELODIE BRIEFER: I used to be using horses once I was younger. And I did few competitions however would like to go for a stroll with the horse.

DANIEL: So Briefer’s heard a number of whinnying over time. She by no means observed something out of the extraordinary till she turned an animal behavioral scientist and started evaluating how completely different animals, together with horses, categorical themselves vocally.

BRIEFER: The first time I actually listened to a horse whinny that I had recorded, I used to be confused ‘trigger I believed there have been two horses, as if there may be two voices on the similar time.

DANIEL: Briefer inspected the sound file extra carefully, and that is when she noticed it – two frequencies produced on the similar time, one excessive and one low.

BRIEFER: So they’ve principally two tones.

DANIEL: Here’s one of many whinnies that Briefer recorded.

(SOUNDBITE OF HORSE WHINNYING)

DANIEL: Let me sluggish it down for you. Listen on the very starting.

(SOUNDBITE OF SLOWED-DOWN HORSE WHINNYING)

DANIEL: A pair issues stood out to Briefer. First, bigger animals have a tendency to provide decrease frequencies, not increased ones. Second, a good variety of birds can produce two simultaneous frequencies like this, however amongst mammals…

BRIEFER: It’s fairly unusual, a minimum of when it seems on a regular basis in a single sort of sound.

DANIEL: So Briefer determined to analyze how horses do it. She first went to a Swiss stud farm and threaded a small digital camera down the noses of 10 breeding stallions till it was simply above their larynxes, a process the animals are conversant in as a part of their common bodily checkups. She then performed feminine whinnies or paraded a mare in entrance of them.

BRIEFER: And they began whinnying, so we might really see what is going on on.

DANIEL: The vocal folds of the larynx vibrated, identical to once we communicate, to provide the low a part of the whinny. In addition, simply above the larynx, horses have this sturdy cartilage, and the video confirmed that cartilage constricting.

BRIEFER: Which makes solely a small opening.

DANIEL: Likely producing a whistle, the high-frequency a part of the whinny. Next, Briefer’s colleagues related with a butcher in France, a rustic the place they eat horses.

BRIEFER: I do know it isn’t the identical in each nation, however there it is fairly frequent.

DANIEL: The butcher supplied half a dozen horse larynxes, which the group blew air by and CT scanned, confirming the outcomes from the stud farm. Finally, the group tracked down a number of stallions with a uncommon illness that tends to paralyze one of many vocal folds and recorded their whinnies. The low tone was partially absent, however the excessive pitch was unaffected. Here’s an instance.

(SOUNDBITE OF HORSE WHINNYING)

DANIEL: Taken collectively, Briefer, who’s now on the University of Copenhagen, concludes {that a} whinny is a novel mixing of vocal fold vibration that generates the low pitch and a whistling above the larynx that produces the excessive pitch. The outcomes seem within the journal Current Biology.

JACOB DUNN: It’s a very fascinating and thrilling growth in our understanding of animal communication.

DANIEL: Jacob Dunn is an evolutionary biologist at Anglia Ruskin University who did not take part within the analysis.

DUNN: So we all know how they do it. The subsequent query can be, why do they do it?

DANIEL: Answer would possibly lie in earlier work of Elodie Briefer which urged the 2 tones of a whinny seem to encode completely different items of emotional info.

BRIEFER: The highest one signifies whether or not the emotion is nice or disagreeable, after which the opposite one signifies whether or not the emotion is intense or not.

DANIEL: Offering insights straight from the horse’s vocal tract. For NPR News, I’m Ari Daniel.

(SOUNDBITE OF GITKIN’S “CHICHA NOLA”) Transcript supplied by NPR, Copyright NPR.

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