Several thousand years ago a person probably young and male and therefore reckless did something that altered the course of human history. He jumped on the back of a horse and went for a ride.
It wasn't an obvious thing to do. Humans had coexisted with horses for at least twenty thousand years before this. Horses figure prominently in paintings on the walls of caves in southwestern Europe that date to thirty thousand years ago. These horses were objects of human prey; though hard to catch, being swift of foot, they were tasty when roasted.
At some point horses became domesticated in the same way as cattle and sheep. Horse meat was still a principal attraction, but now it was complemented by mare's milk.
Horses lent themselves to domestication by virtue of being herbivores and social. Humans managed to domesticate carnivorous canines, but those critters were small next to horses. No one ever tried to domesticate grizzly bears.
The social part of the equation was equally important. Horses, like dogs, are used to following a leader. The trick for humans in both cases was to make one of themselves the leader in lieu of the head horse or top dog. Cats, an individualistic tribe, are only partially domesticated even today, certainly by comparison with dogs. Herding cats is a metaphor for a hopeless assignment.
Horses in those ancient times were smaller than modern horses. They were comparable in size to the ponies favored by Indian tribes in the American West. Yet like those ponies, they were strong enough to carry a human.
But who was the human who thought to hop on? No one knows, and we'll never find out. This giant leap for mankind took place long before the invention of writing. It almost certainly happened on the Eurasian steppe in the southern part of what would be the Soviet Union during most of the 20th century.
It transformed two activities central to the success of pre-modern human societies: hunting and war.
Mounted hunters could range much farther than hunters afoot. In the first instance, riding made the riders much better at controlling horses, which the riding peoples continued to exploit for flesh and milk. In the competition among human tribes, the better hunters pushed aside the less able.
When the competition turned violent, mounted warriors had a huge advantage over soldiers who fought on foot. Cavalry could cover in an hour what took infantry a day. When the riders learned to fight directly from horseback, the horses amplified their power and ability to intimidate.
In human history, the horse proved almost uniquely adapted to being ridden. In a few places humans learned to ride camels and elephants; in a few more places, cattle and buffalo. But the bovines were too slow, the elephants too big, and the camels too cussed to form the kind of species bond that developed between humans and horses.
How long it took humans to adapt their cultures to horse riding is hard to say. When the Comanches acquired horses from the Spanish in the early eighteenth century, they needed only a few generations to become full nomads and the scourge of the southern Great Plains. But those horses were already domesticated, and the Comanches could copy and then modify what they saw the Spanish doing. The first horse-people of the stepped doubtless took longer, quite possibly much longer.
But eventually they acquired the capacity to do what the Mongol armies of Genghis Khan mastered: living on horseback, ranging thousands of miles supported by little but the grass the horses grazed and the horse blood and milk the riders drank. The Mongols made tributaries of the peoples in an empire larger than any before it. Arab cavalrymen had earlier spread the teachings of Muhammad west from Arabia to the Atlantic. Mounted Spanish soldiers spearheaded the creation of an American empire that stretched from Tierra del Fuego to Texas.
In time the advantage of horse warriors waned, when armies on both sides of battles galloped into the fray. Phil Sheridan’s Union cavalry smashed Jubal Early’s Confederate cavalry in the Shenandoah Valley campaign of the American Civil War.
Horses gave way to motorized vehicles in the twentieth century. Today horse riding is a hobby and horse racing a spectator sport. Vestiges of the Equine Age persist in terms like horse sense, horsepower and horsing around.
But also in the fact that Arabic is spoken across the Middle East and North Africa, and Spanish in most countries of the Americas. And, more arguably, in the compulsion of Russian leaders to seek geographic buffers against potential enemies from beyond the flat horizons that surround their country.
That's a lot of consequence from climbing on a horse.
There are absolutely zero studies of the economic transition from horse to car.