A new study found that ancient Eurasia was a hotbed of prehistoric sex between Neanderthals and ancestors of modern humans, NBC News reported.
And the genes of these ancient Neanderthals and Denisovans live on today in modern Europeans, Asians and in the Melanesians of Papua New Guinea and other Australasian islands.
The study, published in the journal Science, helps confirm earlier theories that human ancestors didn't interbreed with other hominin species until after they left Africa. There's barely a trace of Neanderthal in Africans living today.
But once they started moving across Europe and Asia, they not only lived side by side, they had a few run-ins.