Neanderthals and Early Humans May Have Engaging in Intimate Contact, Researchers Suggest

From Galápagos albatrosses to polar bears, primates to orangutans, certain species appear to kiss. Now, scientists propose that Neanderthals also engaged in this behavior – and might even have exchanged kisses with early Homo sapiens.

Common Oral Evidence

This isn't the initial instance scientists have proposed Neanderthals and early modern humans were closely connected. In earlier research, scientists have found humans and their Neanderthal relatives shared the identical oral bacteria for millions of years after the two species split, implying they swapped saliva.

"Likely they were kissing," the researcher noted, adding that the concept aligned with studies that has revealed humans of certain genetic backgrounds have bits of ancient genetic material in their genome, demonstrating interbreeding was occurring.

Intimate Spin

"This offers a more romantic spin on ancient interactions," the lead researcher commented.

Publishing in the journal Evolution and Human Behavior, Brindle and her team detail how, to explore the historical roots of intimate contact, they first had to come up with a description that was not limited to how humans smooch.

Defining Kissing

"Previously there were some previous attempts to describe a kiss, but it's largely human-centric, which implies that basically other animals don't kiss. Now we know that they likely engage, it may appear different from what human kissing resembles," said the evolutionary biologist.

Nonetheless, she noted some actions that resembled kissing were distinct activities – such as the chewing and transfer of food, or "mouth contact", seen in aquatic species called French grunts.

Consequently the team developed a description of intimate contact based on social behaviors involving intentional oral interaction with a member of the same species, with some movement of the mouth but no transfer of nutrition.

Study Methods

Brindle explained they focused on accounts of intimate behavior in non-human species from Africa and Asian regions, including primates, apes and orangutans, and employed digital recordings to verify the reports.

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

Evolutionary Origins

The team say the results suggest intimate contact developed approximately 21.5m and 16.9m years ago in the ancestors of the large apes.

The position of Neanderthals on this evolutionary lineage suggests it is probable they, too, engaged in a kiss, the researchers say. But the activity may not have been confined to their own species.

"Reality that modern people engage intimately, the reality that we now have demonstrated that ancient relatives probably kissed, indicates that the both groups are probably did engage," the researcher noted.

Evolutionary Importance

While the evolutionary explanation is debated, Brindle said intimate contact could be used in sexual contexts to potentially increase reproductive success or assist in selecting between partners, while it could assist strengthen connections when practiced in a platonic way.

A separate researcher in the behavior of great apes commented that as kissing behavior was observed in a wide range of apes it was logical its origins lie deep in our evolutionary past, and an analysis of various types of kissing among a broader range of animals might push its origins back further still.

"Behaviors that we think of as characteristics of human life, like intimate contact, are not exclusive to us if we examine carefully at different species," the expert noted.

Social Aspects

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 methods of encouraging confidence and closeness will have been important for eons," she said. "This could represent an concept that seems a bit incongruous to our misplaced ideas of a rather ruthless and aggressive past, but really it ought to be expected that Neanderthals – and even Neanderthals and our human ancestors together – engaged intimately."