Neanderthals and Modern Humans Were Likely Engaging in Intimate Contact, Scientists Propose

From Galápagos albatrosses to polar bears, chimpanzees to orangutans, certain species engage in mouth-to-mouth contact. Currently, researchers suggest that ancient hominins did it too – and might even have locked lips with early Homo sapiens.

Shared Oral Evidence

It is not the first time scientists have proposed ancient relatives and early modern humans were closely connected. In earlier research, scientists have discovered modern people and their thick-browed cousins shared the identical oral bacteria for hundreds of thousands of years after the two species split, suggesting they swapped saliva.

"Likely they were engaging in intimate contact," she said, explaining that the concept aligned with studies that has revealed people of non-African ancestry contain ancient genetic material in their genetic makeup, revealing genetic mixing was at play.

Intimate Interpretation

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

Writing in the publication a scientific periodical, Brindle and colleagues report how, to explore the evolutionary origins of kissing, they first had to come up with a description that was not limited to how people smooch.

Describing Intimate Contact

"Previously there were some efforts to describe a intimate act, but it's very much been human-centric, which means that basically other animals do not engage in this. Currently we understand that they probably do, it may appear different from what our intimate contact resembles," explained the evolutionary biologist.

Nonetheless, she said some actions that resembled intimate contact were distinct activities – such as the chewing and food sharing, or "kiss-fighting", observed in aquatic species known as French grunts.

Consequently the team came up with a definition of intimate contact centered around friendly interactions involving directed oral interaction with a individual of the identical group, with some motion of the oral area but absence of nutrition.

Study Methods

The lead researcher explained they focused on accounts of intimate behavior in primates from the African continent and Asian regions, including primates, chimpanzees and orangutans, and employed online videos to verify the observations.

Scientists then integrated this data with details on the evolutionary relationships between living and ancient types of such primates.

Historical Origins

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

Placement of ancient hominins on this evolutionary lineage means it is likely they, too, indulged in a intimate act, the scientists say. But the activity might not have been limited to their own species.

"Reality that humans engage intimately, the reality that we currently have demonstrated that ancient relatives very likely kissed, suggests that the two [species] are also likely to have engage," the researcher added.

Biological Importance

While the evolutionary explanation is debated, Brindle explained kissing could be employed in reproductive situations to potentially increase 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 great apes commented that as kissing behavior was observed in a wide range of primates it made sense its roots extend far into our evolutionary past, and an examination of different forms of intimate behavior among a broader range of species might push its beginnings back even earlier still.

"Things that we think of as signatures of human life, like intimate contact, are not unique to us if we examine carefully at other animals," he said.

Cultural Aspects

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

"Nonetheless, as people we succeed or struggle on the quality of our emotional bonds, and ways of promoting confidence and intimacy will have been important for millions of years," the professor stated. "It might be an image that seems a bit contradictory to our misplaced ideas of a supposedly aggressive and ancient history, but actually it should be expected that ancient hominins – and even Neanderthals and our human ancestors together – engaged intimately."