around 30 000 years ago deep within a cave in france ancient humans drew a series of animals in
charcoal a group of elegant fearsome cave lions a herd of woolly rhinos with giant horns some locked
in battle a long-eared owl engraved in clay with its head swiveled 180 degrees perched and watching
and perhaps most striking of all a panel of majestic horses in profile all painted by the same
artist these are the oldest known paintings of horses ever discovered the first of many that show
up again and again in cave art from europe from around thirty thousand to twelve thousand years
ago in fact according to some estimates horses are the most frequently represented animal in the art
of this period back when those paintings were made in france in the cave now known as chauvet
horses would have been a source of food for people as well as artistic inspiration but over time our
relationship with horses would shift they would become our companions and the literal workhorses
behind the rise of many cultures and civilizations but do these ancient artworks depict the same wild
horses that we eventually domesticated and do our modern horses descend from just one domesticated
population or did it happen many times in many places answering these questions has been
tricky as we've needed to bring together evidence from art archaeology and ancient dna
because as it turns out the history of humans and horses has been a pretty wild ride
at its heart the story of horse domestication has been so mysterious for so long because
good evidence has been really hard to come by for one thing the wild horses depicted in
ancient artwork the potential ancestors of modern horses no longer exist which might sound weird
because there are plenty of horses that live in wild herds across the world today but these are
all descendants of domestic horses the subspecies equus ferris cabalis that were released or escaped
we call these feral horses as opposed to lineages of horses that were never domesticated which we
call wild horses and at the genetic level feral horses are still indistinguishable from domestic
horses the only potential wild horse that's still around is an endangered subspecies javalsky's
horse also known as the taki or mongolian wild horse and i'm pronouncing it that way because
that's how sir david attenborough pronounces it and he gets the final word with me although
also i have heard it called the p horse which for what it's worth smithsonian calls it the p horse
what was it talking about okay so today there are only a few thousand of them spread across
several populations in europe and asia and we're still debating whether or not these horses were
ever domesticated at any point in time by anyone if not then they're the only living horses that
could truly be described as wild they're the last living insight into what the ancient wild
horse populations of eurasia might have been like and they bear a striking resemblance to the most
ancient depictions of horses with their short stocky necks and rigid bristly manes you gotta
hand those ancient artists they just really nailed it but javalsky's horses don't bridge
the gap between those ancient artworks and our modern horses because the genetics are pretty
clear they're not the ancestors of modern domestic horses they don't even have the same number of
chromosomes so where did modern horses come from well for a while we thought that they might trace
back to a 5 500 year old settlement in kazakhstan called bowtie and in one of our earlier episodes
about horse evolution we even said i think actually i was the one who said this that that
place was the origin of modern domesticated horses but the science has changed a lot since then
starting in 1993 archaeologists began finding a huge number of horse remains around bow tie
and in 2009 they reported the discovery of pottery that contained chemical residues
from horse meat and milk fat they even found horse teeth with wear patterns that suggested that the
horses had been bridled and maybe even ridden but then in 2018 the connection between bowties
horses and our modern horses was challenged by geneticists who took another look at the remains
they concluded that the horses from bow tie had little to no genetic connection with modern horses
in fact they were indistinguishable from zawalski's horses and then in 2021
researchers reevaluated the teeth and argued that those wear patterns could have happened naturally
they even found similar patterns on the teeth of ancient wild horses that had never come into
contact with humans they proposed that the people of bow tie hadn't domesticated horses at all
but instead we're just harvesting them from the wild for food so we still don't know for
sure when the first domestication of horses took place or how many times it happened after all it
might be that many different cultures domesticated horses independently and just didn't leave behind
any evidence either archaeological or genetic but thanks to a huge study of ancient dna we finally
have a good understanding of the domestication event that really matters to us the one that
gave rise to all of our modern horses in a paper published in 2021 a team of over 160 researchers
sequenced the genomes of 273 ancient horses from across eurasia covering the last 50 000 years
and they found that up until around 4 000 years ago eurasia had a diverse community
of wild horses with a lot of genetically distinct lineages spread across the region
then pretty suddenly one lineage of forces just exploded spreading rapidly across the continent
and replacing other horses as it went this sudden shift marked the rise of the domestic lineage
that all of our modern horses descend from and the researchers were able to pinpoint the origin of
this lineage to the region of what's now russia around the volga and don rivers there around 4
200 years ago people began domesticating and breeding those horses in huge numbers
okay but so what made these particular horses the direct ancestors of our modern ones
so successful well it seems that they had some key genetic variants that breeders probably selected
for one of the variants changed the function of a gene called gsdmc which seems to be involved
with the spine potentially giving these horses a stronger back making them ideal for carrying the
heavy weights of people chariots and goods another one affected a gene called zfpm1 which is actually
involved in the brain chemistry that affects mood regulation possibly making the horses less anxious
and skittish and more docile so they are easier to handle and breed by around 3 500 years ago
the modern domestic horse had spread far and wide across eurasia and replaced the other populations
of horses and today their descendants all over the world come in many different shapes and sizes from
small ponies to massive draft horses who can all trace their homeland back to the grassy step of
russia over 4 000 years ago without these horses human history would probably be unrecognizable to
us nearly everywhere they went they transformed the way we traveled farmed and waged war
almost overnight in evolutionary terms and we still find horses just as fascinating
and beautiful and mesmerizing as those ancient artists in france did thirty thousand years ago
and we're not horsing around when we thank this month's eontologists
chase archambault colton mikhail afridi annie and eric higgins john davison ing jake hart
and melanie lamb carnivale by becoming an e night at patreon.com eons you can get fun
perks like submitting a joke for us to read like this one from philip what kind of candy
do paleontologists like popping rocks i mean yeah okay and as always thank you for joining
me in the constantine haza studio subscribe at youtube.com eons for more journeys in deep time
you