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

Among seabirds to polar bears, chimpanzees to great apes, various animals appear to kiss. Currently, scientists propose that Neanderthals did it too – and possibly exchanged kisses with early Homo sapiens.

Common Oral Clues

This isn't the initial instance experts have suggested Neanderthals and early modern humans were closely connected. Among previous studies, scientists have found humans and their thick-browed cousins shared the identical oral bacteria for millions of years after the evolutionary divergence, suggesting they swapped saliva.

"Probably they were kissing," the researcher noted, adding that the concept aligned with studies that has revealed people of non-African ancestry have bits of Neanderthal DNA in their genetic makeup, demonstrating genetic mixing was occurring.

Intimate Interpretation

"This offers a different spin on ancient interactions," Brindle said.

Publishing in the publication a scientific periodical, Brindle and her team detail how, to investigate the historical roots of intimate contact, they first had to develop a description that was not restricted by how people kiss.

Describing Kissing

"Previously there were some efforts to describe a intimate act, but it's largely human-centric, which means that essentially other animals don't kiss. Now we understand that they probably do, it may appear different from what human kissing looks like," said Brindle.

However, she noted some behaviors that looked like kissing were something rather different – such as the chewing and food sharing, or "mouth contact", seen in aquatic species known as certain marine animals.

As a result the team came up with a description of kissing based on social behaviors involving directed mouth-to-mouth contact with a member of the identical group, with some movement of the oral area but no transfer of nutrition.

Study Methods

Brindle explained they focused on accounts of intimate behavior in primates from the African continent and Asia, including bonobos, chimpanzees and orangutans, and employed digital recordings to verify the observations.

The researchers then integrated this information with information on the genetic connections between living and ancient types of such primates.

Historical Origins

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

The position of Neanderthals on this evolutionary lineage suggests it is probable they, too, engaged in a kiss, the researchers conclude. But the behavior might not have been limited to their specific group.

"The fact that humans kiss, the fact that we currently have demonstrated that ancient relatives very likely engaged, indicates that the two [species] are probably did kissed," the researcher noted.

Biological Significance

Although the scientific reasoning is discussed, the expert explained kissing could be used in reproductive situations to potentially enhance mating outcomes or help choose between mates, while it might help strengthen connections when used in a platonic way.

Another expert in the behavior of primates commented that as kissing behavior was seen in a broad spectrum of apes it was logical its roots lie deep in our ancient history, and an examination 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 characteristics of our species, like intimate contact, are not exclusive to us if we look closely at different species," the expert noted.

Social Elements

Another professor explained that kissing had a cultural element as it was not common to all societies.

"Nonetheless, as people we succeed or struggle on the strength of our relationships, and ways of promoting confidence and intimacy will have been significant for millions of years," the professor stated. "It might be an image that appears a bit incongruous to our misplaced ideas of a supposedly aggressive and ancient history, but actually it ought to be no surprise that Neanderthals – and including them and our human ancestors collectively – engaged intimately."