Neanderthals and Early Humans Were Likely Kissing, Scientists Propose

From Galápagos albatrosses to Arctic mammals, primates to great apes, various animals appear to kiss. Now, scientists suggest that Neanderthals also engaged in this behavior – and possibly exchanged kisses with modern humans.

Common Oral Evidence

It is not the first time experts have suggested Neanderthals and Homo sapiens were intimately acquainted. Among earlier research, scientists have discovered humans and their thick-browed cousins shared the identical oral bacteria for millions of years after the evolutionary divergence, implying they exchanged oral fluids.

"Likely they were kissing," she said, explaining that the idea chimed with research that has found humans of certain genetic backgrounds have bits of Neanderthal DNA in their genetic makeup, revealing interbreeding was occurring.

Romantic Spin

"This offers a more romantic perspective on human-Neanderthal relations," the lead researcher commented.

Publishing in the journal Evolution and Human Behavior, the researcher and her team detail how, to explore the evolutionary origins of kissing, they first had to come up with a definition that was not limited to how people kiss.

Describing Intimate Contact

"Previously there were some previous attempts to define a intimate act, but it's largely focused on humans, which implies that essentially other animals don't kiss. Now we understand that they probably do, it might just not look from what human kissing resembles," said the evolutionary biologist.

However, she noted some actions that looked like kissing were distinct activities – such as the chewing and transfer of food, or "kiss-fighting", observed in fish called French grunts.

Consequently the research group developed a definition of intimate contact centered around social behaviors involving directed oral interaction with a member of the identical group, with some motion of the oral area but no transfer of food.

Research Methods

Brindle said they concentrated on reports of kissing in primates from the African continent and Asian regions, including primates, apes and great apes, and employed online videos to confirm the observations.

Scientists then integrated this information with details on the evolutionary relationships between extant and ancient types of such animals.

Historical Origins

The team say the findings indicate kissing evolved approximately 21.5m and 16.9m years ago in the ancestors of the great primates.

The position of Neanderthals on this family tree suggests it is probable they, too, indulged in a kiss, the scientists say. But the activity may not have been confined to their own species.

"The fact that modern people kiss, the fact that we currently have demonstrated that Neanderthals very likely engaged, suggests that the two [species] are probably did engage," the researcher added.

Evolutionary Significance

Although the evolutionary explanation is debated, the expert said kissing could be employed in reproductive situations to possibly enhance mating outcomes or help choose between mates, while it might help reinforce bonding when used in a platonic way.

Another expert in the behavior of primates said that as kissing behavior was seen in a wide range of primates it made sense its roots lie deep in our ancient history, and an analysis of different forms of intimate behavior among a broader range of species might push its origins back even earlier still.

"Behaviors that we consider as characteristics of human life, like kissing, are not unique to us if we look closely at other animals," he said.

Cultural Aspects

Another professor said that intimate contact had a social component as it was not universal to all societies.

"However, as humans we thrive or fail on the strength of our relationships, and ways of encouraging confidence and intimacy will have been significant for eons," she said. "It might be an concept that seems a bit incongruous to our misplaced ideas of a rather ruthless and aggressive past, but actually it ought to be no surprise that Neanderthals – and including Neanderthals and our own species together – kissed."