Neanderthals and Early Humans May Have Kissing, Researchers Propose

Among Galápagos albatrosses to polar bears, primates to great apes, various animals engage in mouth-to-mouth contact. Now, researchers suggest that Neanderthals did it too – and possibly locked lips with early Homo sapiens.

Common Microbial Evidence

It is not the first time experts have proposed ancient relatives and Homo sapiens were intimately acquainted. In earlier research, researchers have discovered modern people and their thick-browed cousins shared the same mouth microbe for hundreds of thousands of years after the two species split, suggesting they exchanged oral fluids.

"Likely they were kissing," she said, explaining that the idea aligned with studies that has revealed humans of certain genetic backgrounds have bits of ancient genetic material in their genome, revealing genetic mixing was occurring.

Romantic Interpretation

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

Writing in the publication Evolution and Human Behavior, Brindle and colleagues report how, to explore the evolutionary origins of kissing, they first had to develop a description that was not limited to how people smooch.

Defining Intimate Contact

"There have been some previous attempts to describe a kiss, but it's largely human-centric, which means that basically non-human species don't kiss. Now we know that they likely engage, it might just not look from what human kissing resembles," said Brindle.

However, she noted some actions that resembled intimate contact were something rather different – such as the processing and transfer of food, or "kiss-fighting", observed in aquatic species known as certain marine animals.

As a result the team came up with a definition of kissing centered around social behaviors involving intentional mouth-to-mouth contact with a individual of the same species, with some motion of the mouth but absence of nutrition.

Research Methods

Brindle said they concentrated on reports of intimate behavior in primates from Africa and Asian regions, including primates, apes and great apes, and employed digital recordings to verify the reports.

The researchers then integrated this data with information on the genetic connections between extant and ancient species of such primates.

Historical Origins

The team propose the findings suggest intimate contact evolved somewhere between 21.5m and 16.9 million years ago in the ancestors of the large apes.

The position of ancient hominins on this evolutionary lineage means it is probable they, too, indulged in a kiss, the researchers conclude. But the activity may not have been confined to their specific group.

"The fact that modern people engage intimately, the fact that we currently have demonstrated that Neanderthals very likely kissed, suggests that the both groups are probably did kissed," the researcher noted.

Evolutionary Significance

Although the scientific reasoning is debated, the expert explained kissing could be used in reproductive situations to possibly increase mating outcomes or help choose between mates, while it might help reinforce bonding when practiced in a platonic way.

A separate researcher in the activities of primates commented that as intimate contact was observed in a wide range of apes it made sense its roots extend far into our ancient history, and an examination of different forms of kissing among a broader range of animals might push its beginnings back further still.

"Behaviors that we consider as characteristics of our species, like intimate contact, are not unique to us if we look closely at different species," the expert noted.

Cultural Aspects

An archaeology expert said that intimate contact had a cultural element as it was not universal to all human groups.

"Nonetheless, as humans we thrive or fail on the quality of our relationships, and ways of promoting trust and intimacy will have been significant for eons," the professor stated. "This could represent an image that seems a bit contradictory to our misplaced ideas of a rather ruthless and aggressive past, but really it ought to be no surprise that Neanderthals – and including them and our own species together – kissed."