🔗 Share this article Ancient Hominins and Modern Humans Were Likely Engaging in Intimate Contact, Researchers Propose Among Galápagos albatrosses to Arctic mammals, chimpanzees to great apes, various animals appear to kiss. Now, scientists suggest that ancient hominins also engaged in this behavior – and possibly locked lips with early Homo sapiens. Shared Oral Evidence It is not the first time scientists have proposed Neanderthals and Homo sapiens were closely connected. Among previous studies, scientists have found modern people and their thick-browed cousins shared the same mouth microbe for hundreds of thousands of years after the two species split, implying they exchanged oral fluids. "Probably they were engaging in intimate contact," she said, explaining that the idea aligned with research that has revealed humans of non-African ancestry have bits of Neanderthal DNA in their genome, demonstrating interbreeding was at play. Romantic Spin "It certainly puts a more romantic perspective on ancient interactions," Brindle commented. Publishing in the publication Evolution and Human Behavior, Brindle and her team detail how, to explore the historical roots of kissing, they first had to develop a description that was not restricted by how people kiss. Defining Kissing "Previously there were some efforts to define a intimate act, but it's largely human-centric, which implies that essentially non-human species do not engage in this. Now we understand that they probably do, it may appear different from what our intimate contact looks like," said Brindle. However, she noted some behaviors that looked like intimate contact were something rather different – such as the processing and transfer of food, or "mouth contact", observed in fish called French grunts. Consequently the team developed a description of intimate contact centered around friendly interactions involving intentional oral interaction with a member of the same species, with some movement of the oral area but no transfer of nutrition. Study Approach Brindle explained they focused on accounts of intimate behavior in non-human species from the African continent and Asia, including bonobos, chimpanzees and orangutans, and employed digital recordings to confirm the observations. The researchers then integrated this data with information on the evolutionary relationships between living and extinct types of such animals. Historical Origins The team say the results indicate intimate contact evolved somewhere between 21.5m and 16.9m years ago in the predecessors of the great primates. Placement of ancient hominins on this evolutionary lineage suggests it is likely they, too, engaged in a kiss, the scientists say. But the behavior might not have been confined to their specific group. "The fact that humans kiss, the reality that we now have demonstrated that ancient relatives very likely engaged, indicates that the two [species] are probably did kissed," the researcher added. Evolutionary Importance Although the evolutionary explanation is discussed, the expert explained intimate contact could be used in sexual contexts to potentially enhance reproductive success or assist in selecting between mates, while it might help reinforce bonding when used in a non-sexual manner. A separate researcher in the activities of great apes said that as kissing behavior was observed in a wide range of apes it was logical its origins extend far into our evolutionary past, and an examination of different forms of intimate behavior among a wider variety of animals might push its beginnings back further still. "Things that we think of as signatures of human life, like kissing, are not unique to us if we examine carefully at other animals," he said. Social Elements An archaeology expert said that kissing had a social component as it was not universal to all human groups. "Nonetheless, as humans we succeed or struggle on the strength of our relationships, and ways of encouraging confidence and intimacy will have been important for millions of years," she said. "It might be an image that appears a bit contradictory to our misplaced ideas of a supposedly aggressive and aggressive past, but actually it should be expected that Neanderthals – and including Neanderthals and our human ancestors together – engaged intimately."