Ancient Hominins and Early Humans Were Likely Engaging in Intimate Contact, Researchers Propose
Among Galápagos albatrosses to polar bears, primates to great apes, various animals engage in mouth-to-mouth contact. Currently, researchers propose that Neanderthals did it too – and possibly locked lips with early Homo sapiens.
Common Microbial Evidence
It is not the first time experts have suggested Neanderthals and early modern humans were intimately acquainted. In earlier research, researchers have found humans and their Neanderthal relatives shared the same mouth microbe for millions of years after the evolutionary divergence, implying they swapped saliva.
"Probably they were engaging in intimate contact," she said, adding that the concept aligned with studies that has found humans of non-African ancestry have bits of Neanderthal DNA in their genetic makeup, revealing genetic mixing was at play.
Romantic Interpretation
"This offers a different spin on human-Neanderthal relations," the lead researcher said.
Writing in the journal a scientific periodical, the researcher and her team detail how, to investigate the evolutionary origins of intimate contact, they first had to come up with a description that was not limited to how humans kiss.
Defining Kissing
"There have been some previous attempts to describe a kiss, but it's very much been human-centric, which implies that basically other animals do not engage in this. Now we understand that they likely engage, it may appear different from what human kissing looks like," explained Brindle.
Nonetheless, she said some behaviors that resembled kissing were distinct activities – such as the chewing and food sharing, or "mouth contact", observed in fish known as French grunts.
As a result the research group developed a description of intimate contact based on social behaviors involving intentional mouth-to-mouth contact with a member of the identical group, with some motion of the oral area but no transfer of food.
Research Methods
The lead researcher said they focused on reports of kissing in non-human species from the African continent and Asian regions, including bonobos, apes and great apes, and employed online videos to verify the reports.
The researchers then combined this information with information on the evolutionary relationships between living and ancient species of such animals.
Evolutionary Origins
Researchers propose the results indicate kissing evolved somewhere between 21.5m and 16.9m years ago in the ancestors of the great primates.
Placement of ancient hominins on this evolutionary lineage suggests it is likely they, too, engaged in a intimate act, the scientists conclude. But the activity may not have been confined to their specific group.
"Reality that humans engage intimately, the reality that we currently have demonstrated that ancient relatives probably kissed, indicates that the both groups are also likely to have kissed," Brindle noted.
Biological Significance
While the scientific reasoning is debated, the expert explained intimate contact could be employed in sexual contexts to potentially enhance mating outcomes or assist in selecting between mates, while it could assist reinforce bonding when practiced in a platonic way.
A separate researcher in the activities of great apes said that as intimate contact was seen in a broad spectrum of apes it made sense its roots lie deep in our evolutionary past, and an examination of various types of intimate behavior among a broader range of animals might extend its beginnings back further still.
"Things that we think of as characteristics of our species, like intimate contact, are not unique to us if we examine carefully at other animals," he said.
Social Elements
Another professor explained that kissing had a cultural element as it was not common to all human groups.
"Nonetheless, as humans we succeed or struggle on the quality of our emotional bonds, and methods of promoting trust and closeness will have been significant for millions of years," the professor stated. "It might be an image that seems a bit contradictory to our misplaced ideas of a supposedly aggressive and aggressive past, but actually it should be no surprise that ancient hominins – and including Neanderthals and our human ancestors together – kissed."
