Neanderthals and Early Humans Were Likely Engaging in Intimate Contact, Scientists Suggest

From Galápagos albatrosses to Arctic mammals, chimpanzees to orangutans, various animals engage in mouth-to-mouth contact. Now, researchers propose that Neanderthals did it too – and possibly locked lips with early Homo sapiens.

Shared Oral Evidence

It is not the first time experts have proposed Neanderthals and Homo sapiens were intimately acquainted. Among previous studies, scientists have discovered modern people and their Neanderthal relatives shared the same mouth microbe for hundreds of thousands of years after the evolutionary divergence, suggesting they exchanged oral fluids.

"Likely they were engaging in intimate contact," the researcher noted, adding that the concept chimed with research that has revealed people of certain genetic backgrounds contain ancient genetic material in their genetic makeup, demonstrating interbreeding was at play.

Intimate Spin

"This offers a different perspective on human-Neanderthal relations," Brindle commented.

Publishing in the journal a scientific periodical, the researcher and her team report how, to explore the historical roots of intimate contact, they first had to come up with a description that was not limited to how people kiss.

Describing Kissing

"Previously there were some efforts to describe a kiss, but it's largely human-centric, which implies that basically other animals don't kiss. Now we know that they probably do, it might just not look from what human kissing resembles," explained the evolutionary biologist.

However, she noted some actions that looked like kissing were something rather different – such as the chewing and food sharing, or "kiss-fighting", observed in fish called French grunts.

As a result the team came up with a description of intimate contact based on friendly interactions involving intentional mouth-to-mouth contact with a member of the identical group, with some movement of the mouth but absence of nutrition.

Research Methods

Brindle explained they focused on accounts of kissing in non-human species from the African continent and Asian regions, including bonobos, chimpanzees and great apes, and employed digital recordings to verify the reports.

The researchers then combined this information with information on the genetic connections between extant and ancient types of such primates.

Evolutionary Timeline

Researchers propose the results suggest kissing evolved somewhere between 21.5 million and 16.9m years ago in the predecessors of the great primates.

Placement of ancient hominins on this family tree suggests it is probable they, too, engaged in a intimate act, the researchers conclude. But the activity might not have been limited to their own species.

"Reality that modern people engage intimately, the reality that we now have shown that Neanderthals very likely kissed, indicates that the two [species] are also likely to have engage," Brindle noted.

Biological Importance

Although the scientific reasoning is discussed, the expert said intimate contact could be employed in reproductive situations to potentially enhance mating outcomes or assist in selecting between mates, while it might help reinforce bonding when used in a non-sexual manner.

A separate researcher in the behavior of primates commented that as kissing behavior was seen in a wide range of apes it made sense its origins extend far into our ancient history, and an examination of various types of intimate behavior among a wider variety of species might push its beginnings back further still.

"Behaviors that we think of as signatures of human life, like kissing, are not unique to us if we look closely at different species," the expert noted.

Cultural Elements

Another professor explained that kissing had a social component as it was not common to all human groups.

"Nonetheless, as humans we thrive or fail on the strength of our relationships, and ways of promoting trust and closeness will have been important for millions of years," she said. "This could represent an concept that seems a bit contradictory to our misplaced ideas of a rather ruthless and ancient history, but really it should be no surprise that Neanderthals – and even them and our own species together – kissed."