“What happens at Denisova Cave stays at Denisova Cave!” its inhabitants, the Neanderthal and Denisovan subjects under scrutiny, probably used to say, or words to that effect. Little did they know–how could they know?–that 90 thousand years later, give or take, scientists would be prying into their personal lives and getting all up in their business.

There are several archeological sites in the caves of the Altai Mountains of Siberia. The Denisova cave was named for a hermit named Denis who lived there in the late 1700s. I’m pretty sure he was Homo sapiens.

Denisovan DNA, along with Neanderthal DNA, was sequenced completely for the first time in 2010, which led to the initial discovery that both were interbreeding with our Homo sapien ancestors. Before that time, scientists were unaware that the Denisovans ever existed.

Was the sex consensual? Some ask. Hard to say, but remains of all three human groups have been found in the Altai Mountain caves. Apparently Neanderthals were there first, perhaps later coexisting with Denisovans.

A Neanderthal woman and a man from another extinct human group, the Denisovan, got together and produced a child. Scientists have proven this. While many of us would like to know more–was this a romance, or a one-night stand? Were they in love? Did the parents raise their child together? Was interspecies marriage common, or even condoned among their tribes?–it is pretty crazy that we know anything at all about this union. The lovers could never have foreseen this.

After all, these Neanderthal and Denisovan “hominins” or “archaic humans,” as the scientists term them, had no reality TV or social media to let others know what they were up to. Presumably they did not even read or write as a means of recording their history, nor would word of mouth have carried details of their escapades very far, since the Denisova Cave is located in the rugged Altai Mountains of southwestern Siberia, hardly a densely populated area, then or now.

Scientists of the Homo sapiens persuasion, predominantly geneticists, archeologists and anthropologists investigating the lifestyles of the remote and prehistoric, are delirious with excitement over a bone fragment found in the cave, because its DNA shows that this Neanderthal-Denisovan union took place.

For years, this fragment was kicking around unidentified among various other bits of human, bear, hyena and other animal bone dug by researchers from the cave’s strata, until Swedish biologist Svante Paabo identified the fragment as a piece of one of the long bones of a young woman, about 13 years old, whose DNA was half Neanderthal and half Denisovan.

Neanderthals were renowned for their receding chins, massive brow ridges and reputed brutish behavior, at least until geneticists proved that everyone in the world except SubSaharan Africans has Neanderthal ancestors.

Neanderthals’ image has thus improved. Now we know that their brains were larger than ours, and recent artists’ renderings of Neanderthals have become more flattering. We have learned that they may have had red hair and green eyes, used spoken language, created jewelry, entertained abstract thoughts, used symbolism and buried their dead with flowers.

Now extinct, the Denisovans were once a diverse and far-flung people. Far from the mountains of Siberia, Melanesian, aboriginal Australian and Asian people have traces of Denisovan DNA; modern inhabitants of Papua New Guinea possess a high level. In 2021, geneticists discovered that the Ayta Magbukon, a Philippine ethnic group, has the highest known level of Denisovan ancestry in the world, 5 percent of its genome.

We don’t know how Denisovans looked, except that, judging from some molars found in the cave, their teeth were huge, the molars about twice the size of ours.

In June of this year, in a Laotian cave, far from Siberia, an international team of researchers discovered a tooth belonging to a Denisovan.

Scientists now believe that when Homo sapiens, Neanderthals and Denisovans chanced to meet up after leaving Africa they frequently got together to procreate.

“The new find is giving us a peek into an ancient world in which breeding happened freely between hominins from all walks of life,” Harvard geneticist David Reich stated in an interview with “National Geographic.”

“That sort of qualitatively transforms and changes our understanding of the world. And that’s really exciting.”

Have a good week.

(Martha Allen lives in Keene Valley. She has been writing for the News for more than 20 years.)