🔗 Share this article Neanderthals and Modern Humans Were Likely Kissing, Researchers Propose Among Galápagos albatrosses to Arctic mammals, chimpanzees to great apes, certain species engage in mouth-to-mouth contact. Currently, researchers suggest that ancient hominins did it too – and possibly exchanged kisses with early Homo sapiens. Common Microbial Clues This isn't the initial instance scientists have proposed Neanderthals and early modern humans were intimately acquainted. In earlier research, researchers have discovered humans and their Neanderthal relatives possessed the same mouth microbe for hundreds of thousands of years after the two species split, implying they exchanged oral fluids. "Probably they were kissing," the researcher noted, explaining that the idea aligned with studies that has revealed humans of certain genetic backgrounds contain Neanderthal DNA in their genome, revealing interbreeding was occurring. Intimate Interpretation "It certainly puts a different perspective on ancient interactions," Brindle commented. Writing 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 limited to how people smooch. Defining Kissing "There have been some previous attempts to define a kiss, but it's largely human-centric, which implies that essentially non-human species do not engage in this. Currently we know that they probably do, it may appear different from what human kissing resembles," explained Brindle. Nonetheless, she said some behaviors that looked like intimate contact were distinct activities – such as the chewing and food sharing, or "kiss-fighting", seen in fish known as certain marine animals. As a result the team developed a definition of kissing based on social behaviors involving intentional oral interaction with a member of the identical group, with some motion of the mouth but absence of nutrition. Research Methods The lead researcher explained they concentrated on reports of intimate behavior in non-human species from Africa and Asia, including bonobos, apes and great apes, and employed online videos to confirm the observations. Scientists then integrated this information with details on the evolutionary relationships between living and ancient types of such primates. Historical Timeline The team say the findings indicate intimate contact evolved somewhere between 21.5 million and 16.9m years ago in the predecessors of the large apes. The position of ancient hominins on this evolutionary lineage suggests it is likely they, too, engaged in a kiss, the researchers conclude. But the behavior might not have been limited to their specific group. "The fact that modern people kiss, the reality that we currently have shown that ancient relatives very likely engaged, suggests that the both groups are also likely to have engage," the researcher noted. Biological Significance Although the scientific reasoning is discussed, the expert explained intimate contact could be used in sexual contexts to potentially increase mating outcomes or assist in selecting between partners, 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 observed in a wide range of primates it made sense its origins lie deep in our ancient history, and an examination of different forms of kissing among a broader range of animals might extend its origins back even earlier still. "Things that we think of as characteristics of human life, like intimate contact, are not exclusive to us if we examine carefully at other animals," he said. Cultural Elements An archaeology expert explained that intimate contact had a cultural element as it was not common to all societies. "However, as humans we thrive or fail on the quality of our emotional bonds, and methods of promoting trust and closeness will have been important for millions of years," the professor stated. "This could represent an image that appears a bit contradictory to our incorrect assumptions of a rather ruthless and ancient history, but really it ought to be no surprise that Neanderthals – and including them and our own species together – kissed."