🔗 Share this article Neanderthals and Modern Humans May Have Kissing, Scientists Propose From seabirds to polar bears, primates to orangutans, certain species appear to kiss. Now, scientists propose that ancient hominins also engaged in this behavior – and might even have exchanged kisses with modern humans. Shared Oral Clues It is not the first time experts have suggested ancient relatives and Homo sapiens were closely connected. Among previous studies, scientists have discovered modern people and their thick-browed cousins possessed the same mouth microbe for hundreds of thousands of years after the two species split, suggesting they exchanged oral fluids. "Likely they were kissing," she said, explaining that the idea aligned with studies that has revealed people of non-African ancestry have bits of ancient genetic material in their genome, demonstrating interbreeding was at play. Romantic Spin "It certainly puts a different spin on ancient interactions," the lead researcher commented. Writing in the journal a scientific periodical, Brindle and colleagues report how, to investigate the evolutionary origins of intimate contact, they first had to come up with a definition that was not restricted by how people kiss. Defining Kissing "Previously there were some previous attempts to define a kiss, but it's largely focused on humans, which means that essentially non-human species don't kiss. Now we know that they probably do, it may appear different from what our intimate contact resembles," said the evolutionary biologist. Nonetheless, she said some behaviors that resembled kissing were something rather different – such as the processing and transfer of food, or "kiss-fighting", seen in aquatic species known as certain marine animals. As a result the team came up with a description of kissing based on friendly interactions involving intentional mouth-to-mouth contact with a individual of the same species, with some motion of the mouth but no transfer of nutrition. Research Methods The lead researcher said they concentrated on reports of kissing in primates from Africa and Asia, including primates, apes and great apes, and used online videos to confirm the observations. Scientists then combined this information with details on the genetic connections between living and ancient types of such animals. Evolutionary Origins The team propose the findings suggest kissing evolved somewhere between 21.5 million and 16.9m years ago in the ancestors of the large apes. The position of Neanderthals on this evolutionary lineage suggests it is likely they, too, indulged in a kiss, the scientists say. But the behavior may not have been limited to their own species. "Reality that modern people engage intimately, the fact that we now have shown that Neanderthals very likely engaged, indicates that the two [species] are also likely to have engage," the researcher added. Evolutionary Significance While the scientific reasoning is debated, Brindle said intimate contact could be employed in reproductive situations to potentially enhance mating outcomes or assist in selecting between partners, while it could assist strengthen connections when used 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 apes it made sense its origins lie deep in our ancient history, and an analysis of different forms of intimate behavior among a broader range of species might push its beginnings back even earlier still. "Things that we think of as characteristics of human life, like kissing, are not exclusive to us if we look closely at different species," he said. Social Elements An archaeology expert said that intimate contact had a cultural element as it was not universal to all societies. "However, as people we succeed or struggle on the quality of our relationships, and methods of encouraging trust and intimacy will have been significant for millions of years," she said. "It might be an image that seems a bit contradictory to our incorrect assumptions of a rather ruthless and ancient history, but really it should be no surprise that ancient hominins – and including Neanderthals and our own species collectively – engaged intimately."