Neanderthals and Early Humans Were Likely Kissing, Scientists Suggest
Among Galápagos albatrosses to polar bears, chimpanzees to great apes, various animals appear to kiss. Currently, researchers propose that Neanderthals also engaged in this behavior – and possibly locked lips with modern humans.
Shared Oral Clues
It is not the first time scientists have suggested Neanderthals and early modern humans were intimately acquainted. In earlier research, scientists have discovered humans and their thick-browed cousins possessed the same mouth microbe for hundreds of thousands of years after the two species split, implying they exchanged oral fluids.
"Likely they were kissing," she said, adding that the idea aligned with research that has found humans of non-African ancestry have bits of Neanderthal DNA in their genome, revealing interbreeding was occurring.
Intimate Spin
"It certainly puts a different spin on ancient interactions," Brindle said.
Publishing in the publication Evolution and Human Behavior, the researcher and her team detail how, to investigate the evolutionary origins of kissing, they first had to develop a description that was not restricted by how people smooch.
Defining Intimate Contact
"Previously there were some efforts to describe a intimate act, but it's very much been human-centric, which means that essentially other animals do not engage in this. Currently we understand that they likely engage, it may appear different from what human kissing resembles," explained the evolutionary biologist.
However, she said some actions that resembled intimate contact were distinct activities – such as the processing and transfer of food, or "mouth contact", seen in aquatic species known as certain marine animals.
As a result the team came up with a definition of intimate contact based on social behaviors involving intentional mouth-to-mouth contact with a member of the identical group, with some movement of the oral area but absence of nutrition.
Study Methods
The lead researcher explained they concentrated on accounts of kissing in primates from the African continent and Asia, including primates, chimpanzees and great apes, and used digital recordings to confirm the reports.
Scientists then integrated this data with information on the evolutionary relationships between extant and ancient species of such animals.
Evolutionary Origins
Researchers propose the results indicate kissing evolved approximately 21.5m and 16.9 million years ago in the predecessors of the large apes.
The position of Neanderthals on this evolutionary lineage suggests it is probable they, too, indulged in a kiss, the researchers conclude. But the behavior might not have been limited to their specific group.
"The fact that modern people kiss, the reality that we now have demonstrated that Neanderthals probably kissed, indicates that the two [species] are also likely to have kissed," Brindle added.
Biological Significance
Although the evolutionary explanation is discussed, the expert explained intimate contact could be used in reproductive situations to potentially enhance mating outcomes or assist in selecting between mates, while it could assist strengthen connections when practiced in a platonic way.
A separate researcher in the activities of primates commented that as kissing behavior was seen in a wide range of apes it made sense its origins lie deep in our ancient history, and an examination of different forms of kissing among a wider variety of species might push its beginnings back even earlier still.
"Behaviors that we think of as characteristics of human life, like kissing, are not exclusive to us if we look closely at different species," he said.
Social Elements
Another professor explained that intimate contact had a social component as it was not universal to all human groups.
"Nonetheless, as people we succeed or struggle on the strength of our emotional bonds, and methods of promoting trust and closeness will have been important for millions of years," the professor stated. "This could represent an image that appears a bit incongruous to our misplaced ideas of a supposedly aggressive and ancient history, but really it should be expected that Neanderthals – and even Neanderthals and our own species collectively – engaged intimately."
