It's my time to shine as a horse girl!!
These horses went extinct in the wild 60 years ago! They were reintroduced in other parts of Mongolia and Central Asia earlier than they were reintroduced on the Steppes, but having them back here has been generational conservation work. It's truly amazing.
These horses and other kinds of horses are probably different branches of evolution, which is CRAZY AWESOME. Modern horse breeds trace back to one branch, and these dudes evolved separately. They have 33 chromosome pairs whereas the horse you're used to seeing in movies and TV shows (or riding if you too are a horse girl - gender neutral title of expertise) have 32.
Despite this, you can interbreed these two species and they will have fertile offspring. That's really rare! (A common equine cross between species, the mule, is an always-sterile offspring of a donkey and a horse, for instance).
I did have to look the exact numbers up here, full disclosure, but it's believed that Przewalski's horses and other breeds have a common ancestor about between 160,000 and 38,000 years ago
The horses you see on cave art? These guys!
It's likely that Attila the Hun and his armies rode these horses (though hard to prove decisively)
Part of the conservation efforts around them involved CLONING to avoid a genetic bottleneck. ISN'T THAT DOPE. You can read more about that here
These are the only truly wild horses. All other "wild" horses -- Australian brumbies and American mustangs, for instance -- are feral descendants of domesticated horses, which is partly why you can see such a wide range of heights, colors, conformations, etc in those populations.
Anyway. This is incredible news and this species of animal is very special, very ancient, and very cool.