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

Among Galápagos albatrosses to polar bears, chimpanzees to orangutans, certain species engage in mouth-to-mouth contact. Now, scientists propose that Neanderthals did it too – and possibly locked lips with early Homo sapiens.

Common Oral Clues

It is not the first time experts have proposed ancient relatives and early modern humans were intimately acquainted. In previous studies, scientists have discovered modern people and their thick-browed cousins shared the identical oral bacteria for millions of years after the two species split, suggesting they swapped saliva.

"Likely they were kissing," the researcher noted, adding that the idea aligned with studies that has revealed people of certain genetic backgrounds have bits of Neanderthal DNA in their genome, revealing interbreeding was at play.

Intimate Spin

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

Publishing in the publication a scientific periodical, Brindle and colleagues report how, to explore the historical roots of intimate contact, they first had to develop a description that was not limited to how humans kiss.

Describing Intimate Contact

"There have been some previous attempts to describe a intimate act, but it's very much been focused on humans, which means that basically other animals don't kiss. Currently we know that they likely engage, it might just not look from what human kissing looks like," said the evolutionary biologist.

Nonetheless, she said some actions that looked like kissing were something rather different – such as the chewing and food sharing, or "mouth contact", observed in fish called French grunts.

As a result the team came up with a description of intimate contact based on friendly interactions involving directed oral interaction with a individual of the identical group, with some movement of the mouth but no transfer of food.

Study Approach

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

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

Evolutionary Origins

Researchers propose the results suggest kissing developed approximately 21.5 million and 16.9m years ago in the predecessors of the large apes.

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

"Reality that modern people engage intimately, the reality that we now have demonstrated that Neanderthals probably engaged, suggests that the two [species] are probably did kissed," Brindle noted.

Evolutionary Significance

While the evolutionary explanation is debated, the expert explained intimate contact could be employed in reproductive situations to possibly enhance reproductive success or help choose between mates, while it might help reinforce bonding when practiced in a non-sexual manner.

A separate researcher in the activities of primates commented that as intimate contact was observed in a wide range of primates it was logical its roots extend far into our ancient history, and an analysis of different forms of kissing among a broader range of species might extend its beginnings back even earlier still.

"Behaviors that we think of as signatures of our species, like kissing, are not exclusive to us if we look closely at different species," he said.

Social Elements

An archaeology expert said that kissing had a cultural element as it was not common to all societies.

"However, as humans we succeed or struggle on the quality of our relationships, and methods of encouraging trust and intimacy will have been important for millions of years," the professor stated. "This could represent an image that appears a bit contradictory to our misplaced ideas of a supposedly aggressive and aggressive past, but actually it should be expected that Neanderthals – and even Neanderthals and our own species together – engaged intimately."