One Site, 300,000 Years, Three Species

 It's called Denisova Cave, and it's where we found the first evidence of an Asian human subspecies, the Denisovans.

But it actually has more of a history than that. Based off of "environmental DNA" studies (where we get DNA fragments from the soil), Denisova Cave was used (possibly occupied) by humans for 300,000 years.

And it held three different subspecies.

Oh, and we also found a fossil there of a kid who had one Denisovan parent and one Neanderthal.

The Denisovans found the place first, lived there for a long time then left or disappeared. A different ethnic group of Denisovans then took over. Neanderthals showed up in different groups, and appear to have been cheerfully making babies with the Denisovans.

And then 45,000 years ago, "modern" humans also reached the cave...and there were both Neanderthals and Denisovans there.

We can't be sure, but Denisova Cave appears to have ended up with three different human subspecies at once.

So...what was so special about this site? That part we don't know.

We don't even know, yet, if it was special or if this kind of thing was going on all over the place.

What we do know is that our ancestors weren't necessarily particularly fussy about...ya know. Mating.