The Return of the Horse:
A Continent Reunited with Its Animal

To understand what happened when the Spanish landed in America with their horses, we first have to go back a very long way, more than fifty million years. It was here, on this continent, that the horse first came into being.

North America, the Cradle of the Horse

The earliest known equid bears a name that says everything about its modesty: Eohippus, the "dawn horse." Discovered in the Eocene strata of the Wind River Basin in Wyoming, this ancestor stood no more than twelve inches (30 cm) at the withers. A forest-dwelling, digitigrade animal, it still had four toes on its forefeet and three on its hind feet. Nothing in its stocky frame hinted at the Quarter Horse or the Thoroughbred.

And yet everything descends from it.

For tens of millions of years, equids evolved exclusively on North American soil. The climate shifted, the forests receded, the great grasslands spread, and the horse adapted. Its limbs lengthened, its toes reduced, its teeth strengthened to grind grasses. It grew taller and faster. The genus Equus (the direct ancestor of the modern horse) appeared about four million years ago, still in North America.

It was from this cradle that the horse conquered the world. Two to three million years ago, populations crossed the Bering land bridge into Asia, then spread through Europe, the Middle East, and Africa. It was there, on the Eurasian steppes, that Equus caballus would be domesticated (the earliest evidence, still debated, comes from the Botai culture of Central Asia, around 3500 BCE, but the lineage from which every modern breed descends appears only later, in the steppes of the lower Volga-Don region, around 2200 BCE), and it was there that the horse became the animal that would transform human history.

The Great Disappearance

Then came the silence. About ten thousand years ago, at the end of the Pleistocene, a wave of mass extinctions swept across North America. The mammoth, the giant sloth, the American lion, the horse: all disappeared. Scientists still debate the exact causes: abrupt climate change, habitat fragmentation, hunting pressure from the first humans to reach the continent, or, most likely, a combination of these factors. What is certain is the result: for the first time in tens of millions of years, the continent that had invented the horse no longer had a single one.

For ten thousand years, the great North American prairies were roamed by bison, but no longer by the hooves of Equus. The peoples who settled there, who built their societies and flourished on those plains, held no living memory of the animal.

The Return: 1493, 1519

Everything changed in 1493. On his second voyage to the Americas, Christopher Columbus landed in the Caribbean with the first horses, Andalusians, Barbs, and Iberian crosses shaped by centuries of selective breeding in Spain and North Africa. In 1519, Hernán Cortés brought the horse to the mainland itself, in Mexico. By 1525, he had put together a founding breeding herd there. In 1531, horses reached South America; in 1538, Florida. By 1553, an estimated ten thousand or more horses were running free in Mexico alone.

The animal had traveled an extraordinary road: born in America, migrated to Eurasia, domesticated on the steppes, refined in Iberia over centuries, and now back on the land of its ancestors.

The Question That Divides: Reintroduction or Return?

Here a deep rift opens between Western science and Indigenous oral traditions, one that deserves to be laid out honestly.

For most archaeologists and paleontologists, the modern horse is a reintroduced species: Equus populations vanished from the continent ten millennia ago, and the horses brought back by the Spanish have no direct genetic continuity with their prehistoric North American ancestors. This is the position of the current scientific consensus, confirmed by analyses of ancient DNA.

But many Indigenous peoples dispute this account. Lakota oral traditions hold that the people have had a relationship with the horse "since time immemorial." The Oglala Lakota ethnohistorian Yvette Running Horse Collin, in her doctoral dissertation, argues that the horse never truly disappeared from the Americas, and that the arrival of Spanish horses in 1519 was a reunion rather than a reintroduction. The Ojibwe and other northern nations speak of their "spirit horses," which they say they lived alongside long before the Europeans arrived. These accounts are not idle legends: they attest to a deep cultural memory that Western science long refused to take seriously.

The archaeological record does settle this debate, but the answer changes depending on which question is asked. A study published in 2023 in the journal Science, by the archaeologist William Taylor (University of Colorado Boulder) and more than eighty co-authors (including representatives of the Lakota, Comanche, and Pawnee nations) used genomic, isotopic, and radiocarbon analyses to show that Native American peoples were integrating the horse into their societies as early as the first half of the 17th century, several decades before European colonists physically reached those regions. The horse had traveled from one tribe to the next, carried along trade networks and intertribal alliances, long before white men were there to observe and record it.

As William Taylor sums it up: "We show that decades, and in some cases centuries, before the first Europeans set foot in many parts of the West, Indigenous peoples were raising, riding, and caring for their horses, and had integrated them into the social, economic, and ceremonial aspects of their lives."

On biological continuity, however, the same study reaches the opposite conclusion: the horses recovered from Native American sites are of Iberian ancestry, and the genomic data detect no gene flow between the North American equids of the Pleistocene and the historical horses. The oral traditions were right about the chronology, then, but the descent of the animals themselves remains unproven. This point is developed in the article From Vaqueros to Modern Arenas — The Iberian Roots: The Spanish Legacy.

This finding overturns the long-dominant narrative that the Pueblo Revolt of 1680 was the one and only event that triggered the spread of the horse. That moment remains pivotal, but it is no longer the beginning of the story. It is a decisive chapter, not the first page.

An Animal Coming Home

One observation remains, at once scientific and almost poetic, that no one disputes: when the Spanish horses set foot again on the great North American prairies, they returned to the very land where their ancestors had evolved for millions of years. The grasses, the ground underfoot, the climate, all of it was written somewhere in their biology. The speed with which they adapted, thrived, and formed hardy wild herds was no accident. It was, in a profound sense, an animal rediscovering its world.

And it was the Indigenous peoples who understood this first, and who made something extraordinary of it.