Tag Archives: horse

Discover Why Horse Sounds Are Unique in Nature

Posted on by
Reply
Understanding Horse Communication

Insights into How Horses Communicate

Horizon International Images/Alamy

Horses are unique in their vocalizations, producing two distinct sounds simultaneously—a low, cow-like moo and a high-pitched whistle from their throats.

Recent research reveals that horse vocalizations exhibit both low-frequency sounds around 200 hertz and high-frequency sounds exceeding 1,000 hertz, a phenomenon known as biphonation. The low-frequency sounds can be attributed to the vibrations of the horse’s laryngeal vocal folds, much like human speech and singing. However, the mechanism for producing the high-frequency sounds in such a large animal remains an intriguing question.

“Humans have coexisted with horses for over 4,000 years, yet equine communication remains partially misunderstood,” explains Tecumseh Fitch from the University of Vienna, Austria.

To investigate this phenomenon, Fitch and his team conducted tests and experiments on horse larynxes sourced from meat suppliers.

“Initially, we observed low-frequency sounds when we blew air into the larynx,” says Fitch. “However, after some adjustments, we successfully elicited high-frequency components.”

This established that both sound components originate from the larynx itself, contrasting with human whistling produced via the lips.

To confirm the whistling mechanism, researchers introduced air and helium—two gases of varying densities—through the larynx. This allowed them to test whether high-frequency sounds resulted from whistle production or tissue vibrations.

“The low-frequency sounds stem from vocal cord vibrations, similar to human singing or cow mooing, and remained unchanged when we altered the gases,” Fitch noted. “Conversely, the high-frequency content varied significantly with higher helium concentrations.”

Endoscopic examinations of live horses revealed that laryngeal muscles contract as the call begins, narrowing the glottis—where the vocal cords reside—and increasing airway resistance. This mechanism forces air through a narrow opening at high speed.

While other small mammals like mice and rats can produce laryngeal whistles, their frequencies are inaudible to humans.

“Horses are unique among mammals for their ability to produce two frequencies at once using their larynx, with whistles being part of their regular vocal repertoire,” Fitch adds.

This research sheds light on a previously undocumented method of aerodynamic whistle production in animals beyond rodents, explains Ben Jankovic at the University of New South Wales, Sydney.

Fitch and his colleagues propose that whistles enhance vocal clarity and transmission distance, although these theories require further investigation.

Topics:

Source: www.newscientist.com

A breeding revolution 4,200 years ago shaped the origins of the modern horse.

Posted on by
Reply

Horse domestication began on the Eurasian steppes

Lina Shatalova/iStockphoto/Getty Images

A genetic study of hundreds of ancient horses suggests that ancient breeders dramatically shortened the horse’s natural development period, starting around 4,200 years ago. This intense breeding allowed the lineage to rapidly expand across Eurasia within a few centuries, according to researchers led by Ludovic Orlando at the Centre for Human Biology and Genomics in Toulouse, France.

“In other words, they controlled horse breeding,” he says, “so this tells us something about the breeding processes behind the success of horse breeding around the world.”

Horses were first domesticated 5,500 years ago by the Botai people in what is now Kazakhstan. The Botai, however, did not spread their horse culture to other regions and eventually went extinct. Horses released back into the wild.

More than 1,000 years later, a different lineage of horse was domesticated in the Pontic-Caspian steppes of southern Russia. This lineage eventually spread worldwide, giving rise to all the domesticated horses we see today, according to Orlando.

To trace the history of horse domestication, Orlando and his team analyzed the genomes of 475 ancient horses dating back 50,000 years in Eurasia. They compared these genomes with those of 71 modern domestic horses representing 40 breeds from around the world, along with six species of the endangered mullein genus (a separate subspecies).

The research found that, except for the Botai, horses were not domesticated before the third millennium BCE, indicating that horses did not play a significant role in early human migration or cultural expansion, as previously suggested, Orlando explained.

DNA analysis showed that horses in the Pontic-Caspian steppe underwent significant inbreeding around 4,200 years ago, likely in an effort to develop specific traits for high-quality riding or chariot horses, according to Orlando.

Through a combination of genome sequencing and carbon dating, scientists estimated that the average time between two successive horse generations, called the generation time interval, was significantly shortened during the same period of inbreeding in the Pontic-Caspian steppes, halving the interval seen in the wild.

“During the domestication bottleneck around 2200 BCE, breeders were able to control horse reproduction so well that generations became faster and faster,” Orlando said.

Orlando suggests that breeders may have achieved this shortening of generation times not by breeding horses at a younger age, but by increasing survival rates. Unlike wild horses, horses in human care are less susceptible to deaths among mares and newborn foals, as they are protected from predators and disturbances that could jeopardize their survival, according to researchers at the University of Veterinary Medicine in Vienna led by Kristin Orlich.

topic:

Source: www.newscientist.com