🔗 Share this article Ancient Hominins and Modern Humans Were Likely Engaging in Intimate Contact, Researchers Propose Among seabirds to Arctic mammals, primates to orangutans, various animals engage in mouth-to-mouth contact. Currently, researchers suggest that ancient hominins did it too – and possibly locked lips with modern humans. Shared Oral Evidence This isn't the initial instance experts have suggested Neanderthals and Homo sapiens were closely connected. Among earlier research, researchers have discovered humans and their Neanderthal relatives shared the identical oral bacteria for millions of years after the two species split, implying they exchanged oral fluids. "Probably they were kissing," the researcher noted, adding that the concept aligned with research that has revealed people of non-African ancestry contain ancient genetic material in their genome, demonstrating interbreeding was occurring. Romantic Interpretation "It certainly puts a different spin on human-Neanderthal relations," the lead researcher said. Publishing in the journal Evolution and Human Behavior, Brindle and her team report how, to investigate the evolutionary origins of kissing, they first had to come up with a description that was not limited to how humans smooch. Defining Kissing "Previously there were some previous attempts to describe a kiss, but it's very much been human-centric, which implies that essentially other animals do not engage in this. Now we know that they probably do, it might just not look from what human kissing looks like," said Brindle. Nonetheless, she noted some actions that resembled intimate contact were something rather different – such as the chewing and food sharing, or "kiss-fighting", observed in fish called French grunts. Consequently the research group developed a description of kissing based on friendly interactions involving intentional oral interaction with a member of the same species, with some movement of the oral area but absence of nutrition. Study Methods The lead researcher explained they focused on accounts of kissing in primates from Africa and Asia, including bonobos, chimpanzees and great apes, and employed digital recordings to verify the observations. Scientists then combined this data with information on the evolutionary relationships between living and extinct types of such primates. Evolutionary Origins Researchers say the findings suggest kissing evolved approximately 21.5m and 16.9 million years ago in the ancestors of the great primates. Placement of ancient hominins on this family tree suggests it is likely they, too, indulged in a kiss, the scientists say. But the activity may not have been limited to their own species. "The fact that humans engage intimately, the reality that we currently have shown that Neanderthals probably kissed, suggests that the two [species] are also likely to have kissed," Brindle added. Biological Significance Although the scientific reasoning is discussed, the expert said kissing could be employed in reproductive situations to possibly enhance mating outcomes or help choose between partners, while it could assist reinforce bonding when used in a platonic way. A separate researcher in the behavior of primates commented that as intimate contact was observed in a broad spectrum of apes it was logical 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 origins back even earlier still. "Behaviors that we consider as characteristics of human life, like intimate contact, are not exclusive to us if we look closely at other animals," the expert noted. Social Aspects Another professor said that kissing had a cultural element as it was not universal to all human groups. "Nonetheless, as humans we succeed or struggle on the strength of our emotional bonds, and methods of promoting confidence and closeness will have been significant for eons," she said. "This could represent an image that seems a bit contradictory to our incorrect assumptions of a rather ruthless and ancient history, but really it should be expected that ancient hominins – and including Neanderthals and our own species collectively – engaged intimately."