Happy Lunar New Year! Celebrate the Year of the Horse with science

The new moon on February 17 marks the start of the Lunar New Year, celebrated in many countries in Southeast and East Asia. According to the Chinese zodiac, it’s also the start of the Year of the Horse, providing a perfect excuse to whinny about the science of horses and their animal relatives.

Domestic horses are the most famous members of the genus Equuswhich also includes a wild relative called Przewalski’s horse, in addition to three species of donkeys and three species of zebras. All trace their roots to North America, which was home to the oldest known horse relatives 55 million years ago. But horses disappeared from the continent at the end of the last ice age; modern equines all originated in Africa and Eurasia, where domestication also took place.

This development changed the history of humans and horses. Horses carried many civilizations to their peak, only to end up as an anachronism in modern society. Revealing scientific research on horse behavior is only decades old, says Sue McDonnell, an equine behavior specialist at the University of Pennsylvania School of Veterinary Medicine.

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Scientific American spoke with McDonnell and Sarah King, a behavioral ecologist at Colorado State University who specializes in horses and other equines, to highlight some of the most interesting science surrounding this year’s featured animals.

LEARN MORE: The surprising new story of the domestication of the horse

Horses are very social

Domestic horses have three basic needs: freedom, forage and friendships with other horses. This is because the social nature of these animals runs very deep.

Let the horses loose and something remarkable happens, McDonnell says. “They immediately reassemble into the social structure they had when we first domesticated them,” she says. In this structure, each herd includes several so-called harems consisting of a stallion and a handful of mares and their offspring, as well as a “bachelor band” composed of related young males who deal with threats to the herd.

Studies have shown that the stallions who have the most foals are also those who have friendly relationships with their mares, not those who rely on aggression and violence. “Equestrian society is really united by bonds of affiliation,” King says.

Don’t despise the clogs

For owners of domestic horses, hooves are a headache: they tend to break and require regular trimming and shoeing. But these problems only arise because of the hard surfaces that domestic horses have to walk on. Wild horses “have no problem,” McDonnell said.

And these horses’ hooves undergo seasonal changes in response to local climate and surfaces, she notes. In the spring and fall, horses tend to develop longer hooves, which act “like little skis” to help the animals navigate softer ground. In winter and summer, when the ground is harder and animals move less, hooves naturally become shorter.

The mixed landscape of wild equine conservation

Among wild equine species, King is most concerned about Africa’s critically endangered wild asses (African Equus), which live around the Horn of Africa. “They live in a very inhospitable environment – ​​there are real deserts there – and of course there are also a lot of political problems in that part of the world,” she says. Animals are also hunted for food and medicine and must compete with livestock for forage.

In contrast, their distant cousins, the Przewalski horses of Central Asia, are recovering after disappearing in the wild in the 1960s. After a careful breeding program in zoos, scientists began reintroducing the horses into the wild in the 1980s. And now, notes King, some populations are completely self-sustaining. “They are a real conservation success story,” she says.

LEARN MORE: The last wild horses are finally returning to their natural habitat

Horses really sense human fear

This one won’t come as a surprise to anyone who has worked extensively with horses, but research published last month experimentally proves that horses can sense human fear. “Our emotions are central when we interact with horses,” said study author Plotine Jardat, a researcher in horse behavior and welfare at France’s National Institute for Research on Agriculture, Food and the Environment. Scientific American at the time.

Better research on exactly how Human emotions affect horses’ responses, which is vital for animal welfare, McDonnell says. For example, a horse’s defensive behavior can easily be misinterpreted as aggression, she notes, and that can make people fearful, which, as the new research shows, can put the horse more on edge, leading to a tricky feedback loop.

LEARN MORE: Horses can sense your fear, bizarre sweating study finds

AI can help owners care for their horses

Horses have spent millennia evolving to avoid predators, which has made them reluctant to show signs of pain or weakness around humans, McDonnell says. In recent years, veterinarians have begun trying to get around this problem by combing through video footage for clues that a horse is sick. Once a horse is alone, she says, “you can detect a lot of subtle behaviors that indicate discomfort.”

But it’s not a quick technique. That’s why McDonnell is working with artificial intelligence specialists to train a system that can scour images of horses to look for the small signals picked up by veterinarians, but much faster than any human can.

Horses Communicate More Creatively Than You Think

If cats meow and ducks quack, horses neigh in stereotypical ways, but they also neigh, neigh, blow, and squeak, and these noises have been, for the most part, overlooked. “We’re starting to understand that there’s probably a lot more communication going on in these noises,” King says. “Understanding the context and the meaning of these noises, I think, is really interesting.”