Neanderthals and Modern Humans Were Likely Kissing, Scientists Propose
Among Galápagos albatrosses to Arctic mammals, chimpanzees to great apes, various animals appear to kiss. Now, researchers propose that Neanderthals did it too – and possibly exchanged kisses with modern humans.
Shared Oral Clues
It is not the first time experts have proposed ancient relatives and Homo sapiens were closely connected. Among earlier research, scientists have found modern people and their thick-browed cousins possessed the identical oral bacteria for hundreds of thousands of years after the evolutionary divergence, suggesting they exchanged oral fluids.
"Likely they were kissing," the researcher noted, adding that the idea aligned with research that has found humans of certain genetic backgrounds contain ancient genetic material in their genetic makeup, revealing genetic mixing was occurring.
Romantic Interpretation
"It certainly puts a different spin on ancient interactions," Brindle said.
Publishing in the journal a scientific periodical, Brindle and colleagues detail how, to investigate the historical roots of kissing, they first had to develop a definition that was not restricted by how people kiss.
Defining Kissing
"There have been some efforts to describe a intimate act, but it's very much been human-centric, which means that essentially other animals don't kiss. Now we understand that they likely engage, it may appear different from what human kissing resembles," explained Brindle.
Nonetheless, she noted some behaviors that looked like intimate contact were distinct activities – such as the processing and food sharing, or "mouth contact", observed in aquatic species known as French grunts.
As a result the research group developed a definition of kissing based on social behaviors involving intentional mouth-to-mouth contact with a individual of the same species, with some motion of the mouth but no transfer of nutrition.
Research Approach
The lead researcher explained they concentrated on reports of kissing in primates from Africa and Asian regions, including bonobos, chimpanzees and great apes, and used online videos to verify the observations.
Scientists then combined this data with information on the evolutionary relationships between extant and ancient types of such animals.
Historical Origins
Researchers say the results suggest intimate contact evolved somewhere between 21.5m and 16.9m years ago in the ancestors of the large apes.
Placement of Neanderthals on this family tree means it is likely they, too, engaged in a kiss, the scientists say. But the activity may not have been limited to their own species.
"Reality that humans engage intimately, the fact that we now have shown that ancient relatives very likely engaged, indicates that the both groups are also likely to have engage," Brindle noted.
Evolutionary Importance
While the scientific reasoning is discussed, Brindle explained intimate contact could be employed in sexual contexts to possibly enhance mating outcomes 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 said that as intimate contact was seen in a wide range of primates it was logical its roots lie deep in our ancient history, and an examination of different forms of kissing among a wider variety of species might extend its origins back further still.
"Things that we consider as characteristics of our species, like intimate contact, are not unique to us if we look closely at different species," he said.
Social Aspects
An archaeology expert explained that kissing had a social component as it was not common to all human groups.
"Nonetheless, as people we thrive or fail on the strength of our emotional bonds, and ways of encouraging trust and intimacy will have been significant for eons," she said. "This could represent an image that seems a bit contradictory to our incorrect assumptions of a rather ruthless and ancient history, but really it should be no surprise that ancient hominins – and even Neanderthals and our own species together – engaged intimately."
