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

From seabirds to polar bears, primates to great apes, certain species engage in mouth-to-mouth contact. Currently, scientists suggest that Neanderthals also engaged in this behavior – and might even have exchanged kisses with early Homo sapiens.

Shared Oral Clues

It is not the first time scientists have proposed Neanderthals and early modern humans were closely connected. Among previous studies, scientists have discovered humans and their Neanderthal relatives shared the identical oral bacteria for hundreds of thousands of years after the two species split, implying they swapped saliva.

"Likely they were engaging in intimate contact," the researcher noted, adding that the idea aligned with studies that has found humans of non-African ancestry have bits of ancient genetic material in their genetic makeup, revealing interbreeding was at play.

Intimate Interpretation

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

Publishing in the journal a scientific periodical, the researcher and colleagues report how, to explore the evolutionary origins of kissing, they first had to come up with a definition that was not limited to how humans kiss.

Describing Kissing

"There have been some efforts to define a kiss, but it's very much been focused on humans, which implies that essentially other animals do not engage in this. Now we know that they probably do, it may appear different from what human kissing looks like," explained the evolutionary biologist.

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

Consequently the team developed a description of kissing based on friendly interactions involving directed mouth-to-mouth contact with a member of the identical group, with some movement of the oral area but no transfer of food.

Research Methods

Brindle said they focused on reports of intimate behavior in non-human species from the African continent and Asia, including primates, apes and great apes, and employed online videos to verify the observations.

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

Historical Timeline

The team propose the results indicate intimate contact evolved somewhere between 21.5m and 16.9 million years ago in the predecessors of the great primates.

The position of Neanderthals on this family tree means it is likely they, too, engaged in a kiss, the researchers conclude. But the behavior might not have been confined to their specific group.

"Reality that modern people kiss, the reality that we now have demonstrated that Neanderthals probably kissed, indicates that the two [species] are probably did engage," the researcher added.

Biological Importance

Although the evolutionary explanation is debated, Brindle explained intimate contact could be employed in sexual contexts to potentially increase reproductive success or help choose between partners, while it could assist strengthen connections when used in a non-sexual manner.

A separate researcher in the activities of primates said that as kissing behavior was observed in a wide range of primates it made sense its origins extend far into our evolutionary past, and an analysis of various types of kissing among a wider variety of species might push its beginnings back even earlier still.

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

Cultural Elements

An archaeology expert said that intimate contact had a social component as it was not common to all societies.

"However, as humans we thrive or fail on the strength of our relationships, and ways of promoting confidence and intimacy will have been important for eons," she said. "It might be an image that appears a bit contradictory to our incorrect assumptions of a supposedly aggressive and ancient history, but really it should be no surprise that ancient hominins – and even Neanderthals and our human ancestors collectively – kissed."