"But then I realized horses are just men-extenders"
How an equine catalyst gave civilization wings
Part 1 of 2, read part 2
Man did not make the horse. You could argue that man made the cow, the sheep, the goat, perhaps the house cat (though I would lean towards felines having bent the will of man to their own ends), and indisputably our best friend, the dog. But not the horse. Man’s brief passionate dalliance with equus barely lasted four millennia, a blink of the evolutionary eye. But in that time, the horse made man and shaped the character of the civilizations we know today.
Horses’ package of indispensable traits were mostly the fruit of millions of years of fortuitous evolutionary forces in the wild, not the outcome of human selection. And yet when we finally accomplished the dream of harnessing horse power for ourselves (an ambition our species might have been nursing for millennia prior, if 17,000-year-old horse-heavy cave paintings by a people who neither ate nor rode them are any sign), mankind finally tasted the kind of superpower civilizational dreams of made of. Astride a sprinting steed, a humble human was suddenly as a god among men; one with a flying horse, man raced like the wind of Eurasian mythos that conveys souls to heaven.
Plugging into horsepower ushered in an age when men in ever-increasing numbers and leveling up to ever more extraordinary superpowers on an ever accelerating schedule…could live as the gods. For hundreds of thousands of years, anatomically modern human beings had merely… subsisted. Like every other species on the planet. In the last 10,000 years, a small elite of humans finally began to live ever better, clambering up from the Malthusian pit into abundance and affluence. But life was still basically ceaseless toil for 99.9% of our species and no matter how many innovations we concocted to lighten our daily load, that toil was powered by human sweat and brawn. Hunting, gathering, eventually even farming, these were all manpowered pursuits.
But as we were coalescing into ever larger groups, our skill at taming and harnessing nature to our own ends increased. We had to shepherd burgeoning flocks. We had to transport goods for trade. We might at times have to get word out to neighbors and far-flung allies, or to send scouts ahead. We had to build structures and fortifications and fend off other aggressive bands of humans. Of course, these essential pursuits entailed endless walking, schlepping, dragging and lifting, collaboration and cooperation and even perilous close-range combat. And the bigger and more interconnected the networks of human bands got, the more onerous this workload grew.
The more, in other words, man needed a superpower. The horse provided us that first taste of life with a superpower. And not just a rather abstract (but still godlike) progression of superpowers like language to writing to printing to telecommunications. An all-purpose superpower. Horsepower supercharged agriculture, transport, communication and warfare. In each case, horses both provided an instant upgrade to human abilities and catalyzed a chain of progressive improvements and innovations that would enable civilizational advancements to compound on ever grander, more awesome scales.
Horses tilled, plowed and harvested, powering ever more complex, specialized farm equipment until entirely mechanized simulacra replaced them. Horses pulled carts, wagons, carriages and stagecoaches until rail, internal combustion, flight and rockets replaced them. Networks of horses sped urgent messages and information the breadth of a continent before giving way to the telegraph, the telephone, the communications satellite, the internet and the smartphone. Horses pulled chariots, enabled lightning raids, ferried knights armed with lances and dragged cannons until tank, aircraft and drone replaced them. The horse, in short, was our prototype tractor, telegraph, train and tank.
But without exception, approaching our core tasks with the rough-draft superpower only a horse could furnish contributed a first spark of inspiration that set off chain reactions of innovations; an equine powerhouse drove unfathomable knock-on effects that culminated in our age of truly mass-scale, globe-spanning civilizations. And all the ease and leisure they entail. It is easy to forget when you’re the one living it that most humans who have ever existed could not fathom many of our citizens’ everyday reality of being able to transport themselves to the other side of the globe overnight, having sent a few dozen informative (or perhaps vapid?) instantaneous missives about their arrival ahead while en route, in between consuming foodstuffs someone else harvested, all while keeping up to date on the latest outrages in high-tech wars being waged on multiple continents. We still pursue versions of all our age-old human activities. We just do so with the aid of truly god-like superpowers. Ours is an age of miracles.
The horse never needed man. Tens of thousands of mustangs galloping free across American scrublands again today readily attest to that. But for a pivotal span of our species’ history, man needed the horse. Horses were our gateway superpower, our original engine of growth, the magic ingredient that drove economic productivity and allowed us to drag ourselves out of the Malthusian trap of subsistence. Today, that rather one-sided love story is behind us. No one can accuse us of co-dependence anymore. It’s the horse’s successor technologies that allow us to live as gods today. But culturally, humans remain a little hung up on the species that helped us remake civilization as we know it.
Screenwriters Greta Gerwig and Noah Baumbauch featured this man-horse bromance prominently in their award-winning script for the 2023 blockbuster, Barbie. They have Ryan Gosling’s Ken announce with his signature doltishness,
At first I thought the Real World was run by men, and then for one minute I thought it was run by horses, but now I realize that horses are just men-extenders. So are cars, buildings, airplanes, EVERYTHING! Everything exists just to expand and elevate the presence of MEN.
Ken’s escape from his sanitized Barbie-centric milieu is marked by his absolute delight in such real-world discoveries as boxing and a stringy mink coat that looks suspiciously like bleached yak. But nothing compares to his wide-eyed passion for two revelations: horses and patriarchy.
The conceit that horses “extend” men or mankind, in every sense of the word is a potent idea. But that linked fascination with patriarchy is powerful, too. Horse societies are always patriarchal. And where our dalliance with horsepower has left us with bewilderingly reduced workloads or truly superhuman powers, conventionally male pursuits are impacted significantly more than female. If we were to compare the daily work of the parents of small children pre-horse with those of their counterparts today… our millennia of harnessing and extending horsepower have clearly altered both sexes’ lives in countless labor-saving ways. But whereas a mother of small children four millennia ago could probably recognize most of the childrearing and homemaking tasks a parent completes today, a male of her time would probably struggle to identify most jobs performed outside the home today. More of men’s conventional workload has proven amenable to mechanization than women’s traditional burdens. Which should perhaps give us pause when research finds disproportionately rising rates of hopelessness among males. God-like powers have presumably always been a human dream. But their pursuit is probably a lot more invigorating than their unearned enjoyment. That, though, is another reflection for another day. Today, let’s explore the genetic history of the horse and its catalytic role in recent human civilization.
The “Alexander Mosaic” is one of the great Macedonian conqueror’s most famous likenesses; he appears charging the forces of the last Achaemenid, Darius III, at the Battle of Issus 2,357 years ago. Though dated to two centuries after Alexander the Great’s death, it was based on a nearly contemporary painting, and faithfully highlights that he led from the front astride his steed. While Greek martial prowess relied on infantry organized in tight phalanxes bristling with pikes, Alexander’s inherited kingdom of Macedonia gave pride of place to their cavalry. The northern Greek region of Thessaly, alongside Macedonia further inland, was famed for its herds of massive steeds; for Alexander the Great, among nobles from his homeland more generally, the horse was not merely an instrument of war, but a way of life. Alexander had a famously profound affection for Bucephalus, the Thessalian charger he tamed at age thirteen and would later ride into battle against Persians, Bactrians and Indians. When Bucephalus fell at the Battle of the Hydaspes, in Pakistan, Alexander founded a city nearby and named it after him.
But Persia’s cavalry-driven conquest was centuries ahead of its time. Rome’s ascent in the centuries after Alexander’s 323 BC death saw infantry rise to dominance again in the form of its legions. The Hellenistic kingdoms of the east and the barbarians of Western Europe both fell before those legions in the five centuries after Alexander. But after Rome’s fall, mounted warriors again swept across Eurasia; horse-borne conquerors like Attila, Genghis Khan and Tamerlane stalked the continent for over a millennium. But sooner or later every action has its natural reaction. And the nomadic tsunami of fleet mounted warriors bursting out of the continent’s heartland soon triggered venerable civilizations all along its periphery to adopt cavalry as their martial backbone. The threat posted by those earliest horsemen begat everything from Europe and Persia’s heavily armored knights and cataphracts, to the light horse archers of the Dar al-Islam and China.
Dogs may be man’s best friend, and our animal companion of longest standing, dating back to before the Last Glacial Maximum, but for two millennia horses were arguably our species’ most consequential animal helpmate, right until their very recent retirement upon 20th-century mechanization. Rome’s fall over 1,500 years ago ushered in the horse's total ascendancy as warfare’s primary offensive weapon. As horses became ubiquitous in agricultural societies, they were soon drafted not just as farm labor but as workaday transport vehicles. No longer exotic luxury goods, the playthings of kings and generals, the horse’s golden age dawned with our equid companions as generalist engines for economic growth, their novel input decisively setting our species on a long-term trajectory of technological change that could only culminate in the workhorse’s own obsolescence. Equine labor built our modern world, or perhaps you could say equine muscle fatefully set us rolling down the road to the Industrial Revolution.
This military and economic revolution had been a long time in the making; in the early Near East donkeys and the Asiatic wild ass drew chariots, wagons and carts. These were smaller and less majestic cousins to the horse, so when the domestic horse, Equus caballus, finally arrived after 2000 BC, it shot to ubiquity all across Eurasia’s battlefields, from Egypt to Mongolia, leaving to its cousins the dreary role of mere pack animal. Drawing the light war chariot, the horse immediately triggered a political revolution, responsible first for the multi-imperial international order of the Late Bronze Age, and later for both the globalized age of the first-millennium Silk Road and the second-millennium Pax Mongolica.
But because of its late domestication, the horse has only recently been subject to artificial selection. Most of its distinctive characteristics have to be understood in the context of natural history because until as recently as the beginning of written history it remained a wild animal. The traits that suit horses to domestication, and perhaps even render them a necessary accelerant for human civilization as we understand it, are not actually products of human selection, but the lucky fruit of unconstrained evolutionary forces on equid ancestors. And those fateful forces date back to over ten million years ago on North America’s grassy plains.
A world of grass
The predecessors of modern equids, a class which encompasses horses, zebras, donkeys and asses, diversified about six million years ago in North America, but their earliest recognizable ancestor is the diminutive Eohippus, or “dawn horse.” Flourishing over 50 million years ago in the forests of North America (fossil remains center around the state of Wyoming), Eohippus’ teeth were adapted to browsing on foliage, not grazing. But by about 10 million years ago North America’s grasslands were dotted with herds of the modern Equus genus’ undisputed ancestor, a 400-pound grazer called Dinohippus. This ancient grazer’s traits reflected the lineage’s adaptation to an emerging ecosystem: grasslands.
Grasses, flowering plants of the family Poaceae, today dominate the planet’s liminal wild spaces between forest and desert. Additionally, all the major cereals are of the Poaceae family, including maize, wheat, rice, oats, barley and millet. About 70% of crops we grow are technically grasses; they still furnish about 50% of human caloric needs. But these selected strains are exceptional; anyone who has plucked a blade of grass from a lawn to munch on sees that humans could never have subsisted on most grasses. Grass is rich in lignin, making it indigestible, as well as silica, which wears down our teeth. Eating grass is not unlike crunching on shreds of fine-grit sandpaper. To consume this tough but abundant forage, animals have developed novel adaptations.
A worldwide shift to grasslands 20 million years ago drove an evolutionary radiation among the animals we know as ungulates: all large grazing mammals with hooves. All ungulates have high-crowned, very long teeth that are extremely tough in order to withstand silica. Horse teeth grow throughout their lives; if they do not consume tough forage, that aggressive pace of growth gets ahead of them and they literally become “long in the tooth.” Equid teeth have a cap of cementum, a tough and calcified mineral on the crowns to mitigate wear and tear. And equid muzzles lengthened over time so they could graze entirely from a standing position without having to crouch or recline. During this process, the diastema emerged between the frontal incisors and the molars in the back. This gap proved immensely handy to our species; it’s where we slot the bit when harnessing a horse.
Equids also developed exceptional speed and endurance to evade predators. And Dinohippus shows the first evidence of the stay apparatus in limbs, where muscles, tendons and ligaments bind so the animal can remain standing, even while drowsing, almost without effort. Horses actually expend about 10% more calories when they lay down than when they stand. Additionally, since equids can flee predators at the first scent of danger much more effectively from a standing position than if they are lying down and have to lurch up, they very seldom lay down.
Grass' relatively poor nutritional quality has also driven other ungulate adaptations to maximize caloric extraction. In contrast to equids, ruminants, who include antelope, cattle and sheep, have a four-chambered stomach and a complex multistage digestive process. Equids, like rhinos and tapirs, instead have a hindgut fermentation system; the processed grass enters a microbially rich pouch, the cecum, just before the large intestine. Intense fermentation breaks down plant fibers, enabling the absorption of nutrients. Hindgut digestion allows for a faster rate of feeding than rumination, so the animal can really inhale its nutrition, thus the phrase “eat like a horse.” This strategy may be more effective in poor-forage environments that require grazing low-quality food constantly. On the Eurasian steppe, the driest and least productive ranges attracted the highest ratio of horse versus other ungulate herds who require richer fare. That hardiness would later come in handy for armies reduced to “living off the land.”
Grasslands’ poor nutritive quality also drove gigantism in ungulates. The larger a warm-blooded animal, the more energetically efficient it is, and this was even more important on the bleak Ice Age steppe-tundra. Most domestic horses weigh over 1,000 lbs. As herbivores increase in size, their energetic cost per pound gradually decreases, and they can survive off lower quality fare in higher volume, that volume being one thing steppe-lands reliably deliver.
Like most ungulates, equids are herd animals, congregating to seek pastureland together and fend off predators cooperatively. In the wild, the largest equid herds are headed by a single stallion. This feature of their social organization made them eminently suitable for taming and domestication by humans, who assumed the stallion’s dominant role.
By the Pleistocene Ice Age 2.6 million years ago, equids had diversified into ancestors of the three modern species: horse, wild ass and zebra. A million years ago, the domestic horse’s ancestor, Equus ferus caballus, migrated over a land bridge from North America into Eurasia, where it then diversified into many subspecies. These animals coexisted with humans and our own cousins, the Neanderthals and Denisovans, for hundreds of thousands of years. They also show up almost immediately in artistic depictions as our species spread into temperate Eurasia. At Vogelherd Cave in Germany, horse figurines date back 30,000 years. They also feature prominently in the tableaus spanning Lascaux’s cave walls, which date to 17,000 years ago. But the earliest equid relationship to humans was not as companion and helpmate; it was simply food. And prehistoric hunters clearly had to be skilled when hunting them; equids are massive creatures who can thunder away at a moment’s notice. For dozens of millennia, between 37,000 and 12,000 years ago, a site in southeastern France saw the slaughter of hundreds of thousands of horses, judging by the vast accumulation of bones. Massive herds passed through the site along their annual migrations between grazing territories, and every year human hunters lay in wait.
But the number of horse bones found in prehistoric middens plummeted as the world warmed and steppe grasslands gave way to forests. Though the horse is prominent in the Magdalenians’ cave paintings at Lascaux 17,000 years ago, the material record suggests that people subsisted overwhelmingly on reindeer. The horse’s persistence in symbolic art perhaps reflects their religious or cultural importance. Perhaps their awe-inspiring combination of mass, grace and speed had already captured the human imagination millennia before humans would learn to lease their suite of gifts as our own superpower.
But horses grew still rarer. Following the Ice Age, they went extinct in their North American homelands. The Yukon horse too seems to have disappeared after 8000 BC, a victim of climate change and overhunting by Paleo-Indians. In Eurasia, horses also vanished across much of their range, with one major exception: the steppe grassland that stretches from Eastern Europe to Mongolia. Horse domestication finally occurred in this ecosystem.
The taming of the horse
Until recently, ambiguity has clouded the modern horse’s origins. But ancient DNA and genomics have now imposed a precise plotline on that nebulous story: all domestic lines today trace back to a population that flourished between the Don and Volga rivers 4,200 years ago, labeled DOM2 by geneticists. A 2024 paper shows that this lineage endured a tight bottleneck followed by a rapid demographic explosion around 2200 BC, exactly the time of the emergence of the lower Volga’s early Sintashta culture. The most parsimonious explanation for this observed pattern is humans suddenly breeding the horses for particular characteristics. Human breeders impose intense selection by culling the breeding pool of stallions to only a few individuals who sire the next generation, which produces the genetic bottleneck. These stallions will have been chosen for some rare confluence of desired traits like robustness and docility. The largest signal of selection is in GSDMC, a gene associated with skeletal structure and vertebrate development, indicating that DOM2 grew more robust, with strengthened spines equipped to draw chariots with ease. The second strongest signal is at ZFPM1, which dampens anxiety, mood shifts and skittishness toward crowds of humans.
This model aligns well with the spread of the Sintashta light war chariot, whose adoption swept West Asia, Europe and China after 2000 BC. The DOM2 lineage reflects selection pressures imposed by the exigencies of military conflict, a known force driving change in human cultural evolution, and clearly likewise relevant for the horse’s biological evolution. This is also when the first metal bits and other tack appear in the archaeological record. But if we conclude from this tidy explanation that this ubiquitous lineage was also humanity’s very first horse domestication event, this runs counter to David Anthony’s thesis in his 2008 The Horse, the Wheel and Language. He argues there that the spread of Indo-European languages occurred via Yamnaya herders’ expansive pastoralism, presumably on horseback, around 3000 BC, long before the DOM2 explosion.
Of course, The Horse, the Wheel and Language was published before genetics was brought to bear on the question of equid domestication. Now, we know for example that around 3500 BC, Kazakhstan’s Botai culture had an attested close relationship with horses. Over 90% of animal remains at those sites came from horses, and their teeth show evidence of bit-wear, while their remains bear skeletal deformations consistent with being ridden. Pots at Botai sites even retain mare’s milk residue. Ancient DNA now suggests the Botai horses had shorter generation times, 3.5 years instead of the 7.5 years for wild herds. Remarkably, DOM2 lineages also seem to reflect those same short breeding times for a few centuries before 2000 BC, during their initial domestication. This indicates a brief intense period of humans selecting their mates earlier in their life cycle, plus more clement domestic living conditions, and thus faster time to reproduction than under wild conditions (and again after the character of the new breed had been set and human interference relaxed). And, it is not entirely true that all horses today descend from DOM2. Mongolian wild horses are feral descendants of the Botai population; or at minimum, the modern population and the ancient one share common ancestry from the eastern steppe populations.
Even in the western steppe, DOM2 may not be the whole story. A 2023 paper Anthony co-authored reports on five human Yamnaya samples from Romania, Bulgaria and Hungary who show changes in bone structure and pathologies associated with horseback riding. Those remains date to between 3021 and 2501 BC, so well before the DOM2 domestication event. An earlier paper Anthony contributed to reported horse-milk dental calculus on individuals at Yamnaya sites in Russia 5,000 years ago. That data is less definitive than ancient DNA, but the high likelihood of the Botai domestication increases the probability of earlier western domestication events as well. This leaves us to ask exactly who these Yamnaya horses were then, if not DOM2, because they appear to have left no genetic impact on European horse populations. Perhaps DOM2’s subsequent arrival drove the extinction of Yamnaya horses? Unlike wild horses, those herds may have been under total human control, and so their vanishing was nearly inevitable when their masters’ taste switched to a superior new lineage.
The early Yamnaya herds were likely tame and probably ridden bareback (since they were presumably too dainty to pull chariots), even if they weren’t shaped by such radical selection as DOM2 was later subject to. It just seems implausible that the rapid Yamnaya expansion across Europe after 3000 BC was pulled off by a nomadic people provisioned only with ambling herds of cattle, sheep and goat. Indeed, Danish archaeologist Kristian Kristiansen, who has studied the steppe expansion into Northern Europe, argues that in the centuries after 3000 BC, bands of young warriors, koryos, played a critical role in the Yamnaya conquest of Northern Europe as outriders and scouts. The Yamnaya advantage over Neolithic farmers may have been that they had koryos dashing around on ponies executing lightning raids. Anthony also notes that horsemen would have allowed the Yamnaya to command far larger herds, increasing their wealth and allowing greater population sizes.
Ultimately, some details remain to be worked out, but DOM2’s universal penetration today is the foundation upon which we can understand how humans have reshaped horses to our own ends. Because equids are polygynous, with one stallion controlling a herd of mares, humans can drive powerful selection effects simply by culling or gelding most males, selecting only a few as breed-worthy studs. Stallions are often difficult to control, and likely were even more challenging before DOM2 became universal. The Y-chromosomal phylogeny of domestic horses coalesces around 2200 BC, and repeatedly bottlenecks thereafter. A second major bottleneck, leading to the dominance of the “Crown” haplogroup, dates to about 1,500 years ago; this one coincides with Arabian horses expanding across Eurasia, leaving only a few isolated Northern European and East Asian lineages. Arabian horses first arrived in Europe with the Muslims in the 8th century, and were taller, more muscular and enjoyed greater endurance than earlier breeds. Most modern horse breeds, including thoroughbreds and the quarter horse, have a predominantly Arabian genetic origin.
The diversification of horses into breeds as distinct as the miniature Falabellas, who weigh just 150 lbs, and the massive Clydesdales, who can top 2,000, is a testament to their versatility over the last 4,000 years. But like the airplane, they were initially primarily a weapon of war, and their impact on the battlefield would transform human societies and redirect world history.
wow man, so amazing. my horse Brandy was a stallion. I was 14. here's a post I wrote about the majesty of the horse, and how man rebelled in some cases.
https://open.substack.com/pub/riclexel/p/no-more-automation?r=bcx26&utm_campaign=post&utm_medium=web
I was under the impression that humans were getting work out of oxen before they domesticated horses. Is that incorrect?