🔗 Share this article Ancient Hominins and Early Humans Were Likely Kissing, Scientists Propose From Galápagos albatrosses to Arctic mammals, chimpanzees to great apes, certain species engage in mouth-to-mouth contact. Now, scientists propose that ancient hominins did it too – and possibly locked lips with modern humans. Shared Oral Clues This isn't the initial instance experts have proposed ancient relatives and Homo sapiens were intimately acquainted. In previous studies, scientists have found humans and their Neanderthal relatives possessed the identical oral bacteria for hundreds of thousands of years after the two species split, suggesting they exchanged oral fluids. "Probably they were engaging in intimate contact," the researcher noted, adding that the concept aligned with studies that has revealed humans of non-African ancestry have bits of ancient genetic material in their genome, revealing interbreeding was occurring. Romantic Interpretation "This offers a more romantic perspective on human-Neanderthal relations," Brindle said. Publishing in the publication Evolution and Human Behavior, the researcher and colleagues report how, to investigate the evolutionary origins of kissing, they first had to come up with a description that was not limited to how people smooch. Defining Kissing "Previously there were some efforts to describe a kiss, but it's largely human-centric, which means that essentially other animals don't kiss. Currently we know that they probably do, it may appear different from what our intimate contact resembles," explained the evolutionary biologist. Nonetheless, she said some actions that resembled kissing were something rather different – such as the processing and transfer of food, or "kiss-fighting", seen in fish known as French grunts. Consequently the team developed a description of kissing centered around friendly interactions involving directed oral interaction with a member of the same species, with some movement of the mouth but no transfer of food. Study Methods Brindle explained they concentrated on accounts of intimate behavior in non-human species from the African continent and Asia, including bonobos, apes and great apes, and employed online videos to verify the reports. Scientists then combined this data with information on the evolutionary relationships between living and ancient species of such animals. Evolutionary Timeline Researchers propose the findings indicate kissing evolved somewhere between 21.5m and 16.9 million years ago in the ancestors of the great primates. The position of ancient hominins on this evolutionary lineage suggests it is likely they, too, indulged in a kiss, the researchers conclude. But the behavior may not have been confined to their own species. "Reality that modern people engage intimately, the reality that we now have demonstrated that Neanderthals probably kissed, indicates that the two [species] are also likely to have kissed," Brindle added. Evolutionary Significance While the scientific reasoning is discussed, Brindle explained kissing could be employed in sexual contexts to potentially increase reproductive success or help choose between partners, while it could assist reinforce bonding when practiced in a platonic way. Another expert in the behavior of primates said that as intimate contact was observed in a broad spectrum of primates it made sense its roots lie deep in our evolutionary past, 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 think of as characteristics of human life, like intimate contact, are not exclusive to us if we look closely at other animals," the expert noted. Cultural Elements An archaeology expert explained that intimate contact had a social component as it was not universal to all societies. "However, as humans we thrive or fail on the quality of our emotional bonds, and methods of encouraging confidence and closeness will have been significant for eons," she said. "This could represent an image that seems a bit incongruous to our misplaced ideas of a rather ruthless and ancient history, but really it ought to be no surprise that ancient hominins – and including them and our own species collectively – kissed."