Ancient Hominins and Early Humans Were Likely Engaging in Intimate Contact, Researchers Suggest
From seabirds to Arctic mammals, primates to orangutans, certain species engage in mouth-to-mouth contact. Currently, scientists propose that ancient hominins also engaged in this behavior – and might even have locked lips with early Homo sapiens.
Common Oral Evidence
It is not the first time scientists have suggested ancient relatives and Homo sapiens were intimately acquainted. In earlier research, scientists have found modern people and their Neanderthal relatives shared the same mouth microbe for hundreds of thousands of years after the evolutionary divergence, suggesting they swapped saliva.
"Probably they were kissing," she said, adding that the concept chimed with research that has revealed humans of non-African ancestry contain Neanderthal DNA in their genome, demonstrating interbreeding was occurring.
Intimate Spin
"This offers a more romantic perspective on ancient interactions," Brindle commented.
Writing in the journal a scientific periodical, the researcher and colleagues detail how, to investigate the historical roots of intimate contact, they first had to develop a definition that was not restricted by how people kiss.
Describing Intimate Contact
"There have been some efforts to describe a intimate act, but it's largely focused on humans, which implies that essentially non-human species do not engage in this. Now we know that they probably do, it may appear different from what our intimate contact resembles," said the evolutionary biologist.
However, she said some actions that resembled intimate contact were something rather different – such as the chewing and food sharing, or "kiss-fighting", observed in fish known as French grunts.
As a result the team developed a description of intimate contact based on social behaviors involving intentional oral interaction with a member of the identical group, with some motion of the mouth but absence of nutrition.
Research Methods
Brindle 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 confirm the reports.
Scientists then combined this information with details on the genetic connections between living and ancient species of such animals.
Historical Timeline
Researchers propose the findings indicate intimate contact developed approximately 21.5 million and 16.9 million years ago in the ancestors of the large apes.
Placement of ancient hominins on this evolutionary lineage suggests it is likely they, too, engaged in a kiss, the scientists conclude. But the activity may not have been limited to their own species.
"The fact that humans engage intimately, the reality that we now have demonstrated that Neanderthals probably engaged, suggests that the both groups are probably did kissed," the researcher noted.
Evolutionary Importance
Although the scientific reasoning is discussed, the expert said kissing could be employed in sexual contexts to potentially enhance reproductive success or help choose between mates, while it might help strengthen connections when practiced in a platonic way.
A separate researcher in the activities of great apes said that as intimate contact was observed in a wide range of primates it made sense its origins extend far into our ancient history, and an examination of different forms of intimate behavior among a broader range of species might push its beginnings back even earlier still.
"Behaviors that we consider as signatures of human life, like intimate contact, are not exclusive to us if we look closely at other animals," the expert noted.
Cultural Aspects
Another professor said that kissing had a cultural element as it was not universal to all societies.
"Nonetheless, as people we thrive or fail on the strength of our emotional bonds, and methods of promoting confidence and intimacy will have been important for millions of years," she said. "This could represent an concept that seems a bit incongruous to our incorrect assumptions of a rather ruthless and ancient history, but really it should be expected that Neanderthals – and including Neanderthals and our human ancestors together – kissed."
