Ancient Hominins and Early Humans Were Likely Engaging in Intimate Contact, Scientists Propose
From seabirds to polar bears, primates to orangutans, various animals appear to kiss. Now, scientists suggest that ancient hominins did it too – and might even have locked lips with modern humans.
Shared Oral Evidence
It is not the first time experts have proposed ancient relatives and early modern humans were closely connected. In previous studies, scientists have found modern people and their Neanderthal relatives possessed the identical oral bacteria for millions of years after the two species split, suggesting they swapped saliva.
"Likely they were kissing," the researcher noted, adding that the concept chimed with studies that has found humans of certain genetic backgrounds have bits of Neanderthal DNA in their genetic makeup, demonstrating interbreeding was at play.
Romantic Spin
"This offers a more romantic perspective on human-Neanderthal relations," Brindle said.
Publishing in the publication Evolution and Human Behavior, the researcher and colleagues detail how, to investigate the historical roots of kissing, they first had to develop a definition that was not restricted by how humans kiss.
Defining Intimate Contact
"There have been some efforts to describe a intimate act, but it's largely focused on humans, which means that basically non-human species don't kiss. Now we understand that they probably do, it might just not look from what human kissing resembles," explained Brindle.
Nonetheless, she said some behaviors that resembled intimate contact were distinct activities – such as the chewing and transfer of food, or "mouth contact", seen in aquatic species known as certain marine animals.
Consequently the team came up with a description of intimate contact based on friendly interactions involving directed oral interaction with a individual of the same species, with some motion of the mouth but absence of nutrition.
Study Approach
Brindle explained they concentrated on reports of intimate behavior in primates from Africa and Asia, including primates, chimpanzees and orangutans, and employed digital recordings to confirm the reports.
Scientists then integrated this data with information on the genetic connections between living and extinct species of such animals.
Historical Timeline
The team propose the findings suggest intimate contact developed somewhere between 21.5m and 16.9 million years ago in the predecessors of the great primates.
The position of Neanderthals on this evolutionary lineage suggests it is probable they, too, indulged in a kiss, the researchers conclude. But the behavior may not have been limited to their specific group.
"Reality that modern people kiss, the fact that we now have demonstrated that ancient relatives probably kissed, suggests that the both groups are probably did kissed," Brindle added.
Biological Importance
Although the scientific reasoning is discussed, the expert said kissing could be employed in sexual contexts to possibly increase reproductive success or assist in selecting between partners, while it might help strengthen connections when used in a non-sexual manner.
Another expert in the activities of primates said that as intimate contact was observed in a wide range of primates it made sense its origins lie deep in our evolutionary past, and an analysis of different forms of kissing among a broader range of species might extend its origins back further still.
"Behaviors that we think of as signatures of human life, like intimate contact, are not exclusive to us if we look closely at other animals," he said.
Social Elements
An archaeology expert said that intimate contact had a cultural element as it was not universal to all human groups.
"However, as humans we succeed or struggle on the quality of our emotional bonds, and methods of encouraging confidence and intimacy will have been significant for eons," the professor stated. "It might be an image that seems a bit incongruous to our incorrect assumptions of a rather ruthless and aggressive past, but really it should be no surprise that Neanderthals – and even them and our own species together – kissed."
