A horse's neigh may be unique in the animal kingdom. Now scientists know how they do it

NEW YORK -- NEW YORK (AP) — Horses whinny to find caller friends, greet aged ones and observe blessed moments similar feeding time.

How precisely horses nutrient that distinctive dependable — besides called a neigh — has agelong eluded scientists.

The whinny is an antithetic operation of some precocious and debased pitched sounds, similar a transverse betwixt a grunt and a squeal — that travel retired astatine the aforesaid time.

The low-pitched portion wasn't overmuch of a mystery. It comes from aerial passing implicit bands of insubstantial successful the dependable container that marque sound erstwhile they vibrate. It's a method akin to however humans talk and sing.

But the high-pitched portion is much puzzling. With immoderate exceptions, larger animals person larger vocal systems and typically marque little sounds. So however bash horses bash it?

According to a caller study, they whistle.

Researchers slid a tiny camera done horses' noses to movie what happened wrong portion they whinnied and made different communal equine sound, the softer, subtler nicker. They besides conducted elaborate scans and blew aerial done the isolated dependable boxes of dormant horses.

The whinny's mysterious high-pitched tones, they discovered, are a benignant of whistling that starts successful the horse's dependable box. Air vibrates the tissues successful the dependable container portion an country conscionable supra contracts, leaving a tiny opening for the whistle to escape.

That's antithetic from quality whistling, which we bash with our mouths.

“I'd ne'er imagined that determination was a whistling component. It's truly interesting, and I tin perceive that now,” said Jenifer Nadeau, who studies horses astatine the University of Connecticut. Nadeau was not progressive with the study, which was published Monday successful the diary Current Biology.

A fewer tiny rodents similar rats and mice whistle similar this, but horses are the archetypal known ample mammal to person a knack for it. They're besides the lone animals known to beryllium capable to whistle done their dependable boxes portion they sing.

“Knowing that a ‘whinny’ is not conscionable a ‘whinny’ but that it is really composed of 2 antithetic cardinal frequencies that are created by 2 antithetic mechanisms is exciting,” said Alisa Herbst with Rutgers University's Equine Science Center, of the survey successful an email.

A large lingering question is however horses' two-toned calls came to be. Wild Przewalski’s horses tin bash thing similar, arsenic tin elks. But much distant equine relatives similar donkeys and zebras can't marque the high-pitched sounds.

The two-toned whinnies could assistance horses convey aggregate messages astatine the aforesaid time. The otherwise pitched neighs whitethorn assistance them explicit a much analyzable scope of feelings erstwhile socializing, said survey writer Elodie Mandel-Briefer with the University of Copenhagen.

“They tin explicit emotions successful these 2 dimensions,” Mandel-Briefer said.

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Associated Press video writer James Brooks contributed to this report.

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