🔗 Share this article Ancient Hominins and Modern Humans Were Likely Engaging in Intimate Contact, Scientists Suggest From seabirds to polar bears, primates to orangutans, various animals appear to kiss. Now, scientists suggest that ancient hominins also engaged in this behavior – and might even have exchanged kisses with early Homo sapiens. Common Microbial Clues It is not the first time experts have proposed Neanderthals and Homo sapiens were closely connected. Among previous studies, scientists have found humans and their Neanderthal relatives shared the identical oral bacteria for hundreds of thousands of years after the two species split, implying they swapped saliva. "Probably they were kissing," she said, adding that the idea aligned with research that has revealed people of non-African ancestry contain Neanderthal DNA in their genome, demonstrating interbreeding was at play. Romantic Interpretation "This offers a more romantic spin on ancient interactions," the lead researcher said. Publishing in the publication Evolution and Human Behavior, Brindle and colleagues detail how, to investigate the historical roots of intimate contact, they first had to develop a description that was not restricted by how people smooch. Describing Kissing "There have been some previous attempts to describe a intimate act, but it's very much been human-centric, which implies that essentially non-human species don't kiss. Currently we understand that they probably do, it might just not look from what our intimate contact looks like," explained Brindle. However, she noted some behaviors that looked like kissing were distinct activities – such as the chewing and food sharing, or "kiss-fighting", observed in aquatic species called certain marine animals. As a result the research group came up with a description of kissing centered around social behaviors involving intentional mouth-to-mouth contact with a member of the same species, with some motion of the mouth but no transfer of food. Study Methods Brindle explained they focused on reports of kissing in non-human species from Africa and Asian regions, including bonobos, chimpanzees and great apes, and used digital recordings to confirm the observations. Scientists then combined this data with details on the evolutionary relationships between living and ancient types of such animals. Historical Origins Researchers propose the results indicate intimate contact developed approximately 21.5 million and 16.9m years ago in the predecessors of the great primates. Placement of ancient hominins on this evolutionary lineage suggests it is probable they, too, engaged in a intimate act, the scientists conclude. But the behavior may not have been confined to their specific group. "Reality that modern people kiss, the fact that we now have demonstrated that Neanderthals probably kissed, indicates that the both groups are probably did kissed," Brindle added. Biological Significance Although the scientific reasoning is discussed, Brindle said kissing could be employed in sexual contexts to possibly enhance reproductive success or assist in selecting between mates, while it might help reinforce bonding when practiced in a platonic way. A separate researcher in the behavior of great apes said that as kissing behavior was observed in a broad spectrum of primates it was logical its origins extend far into our evolutionary past, and an analysis of various types of intimate behavior among a wider variety of animals might extend its origins back further still. "Behaviors that we consider as characteristics of our species, like kissing, are not unique to us if we examine carefully at different species," he said. Social Elements An archaeology expert explained that kissing had a social component as it was not universal to all societies. "However, as humans we succeed or struggle on the strength of our emotional bonds, and ways of encouraging trust and intimacy will have been significant for eons," the professor stated. "It might be an concept that appears a bit contradictory to our incorrect assumptions of a supposedly aggressive and aggressive past, but actually it should be expected that Neanderthals – and including them and our human ancestors together – kissed."