🔗 Share this article Neanderthals and Modern Humans May Have Kissing, Researchers Suggest Among seabirds to Arctic mammals, primates to orangutans, certain species engage in mouth-to-mouth contact. Now, researchers propose that ancient hominins also engaged in this behavior – and possibly exchanged kisses with modern humans. Common Microbial Evidence It is not the first time scientists have suggested ancient relatives and early modern humans were intimately acquainted. In earlier research, scientists have discovered modern people and their Neanderthal relatives possessed the identical oral bacteria for hundreds of thousands of years after the evolutionary divergence, suggesting they exchanged oral fluids. "Likely they were kissing," the researcher noted, explaining that the concept chimed with research that has revealed humans of certain genetic backgrounds contain ancient genetic material in their genetic makeup, revealing interbreeding was occurring. Romantic Spin "This offers a more romantic perspective on ancient interactions," Brindle said. Writing in the journal a scientific periodical, Brindle and colleagues report how, to explore the historical roots of intimate contact, they first had to develop a definition that was not limited to how humans smooch. Describing Kissing "There have been some efforts to describe a kiss, but it's largely human-centric, which implies that basically other animals do not engage in this. Now 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 intimate contact were distinct activities – such as the chewing and food sharing, or "kiss-fighting", seen in fish known as French grunts. Consequently the team developed a description of kissing based on social behaviors involving directed mouth-to-mouth contact with a member of the same species, with some motion of the mouth but no transfer of nutrition. Study Methods The lead researcher said they focused on reports of kissing in primates from the African continent and Asian regions, including bonobos, chimpanzees and orangutans, and employed online videos to verify the observations. The researchers then integrated this information with details on the genetic connections between living and extinct types of such primates. Evolutionary Timeline The team say the results indicate intimate contact developed somewhere between 21.5 million and 16.9 million years ago in the predecessors of the large apes. The position of Neanderthals on this family tree means it is likely they, too, engaged in a intimate act, the scientists say. But the behavior might not have been limited to their own species. "Reality that modern people kiss, the reality that we currently have demonstrated that Neanderthals probably engaged, suggests that the both groups are also likely to have engage," Brindle added. Biological Significance While the evolutionary explanation is debated, the expert said kissing could be used in reproductive situations to potentially increase reproductive success or assist in selecting between mates, while it might help strengthen connections when used in a platonic way. Another expert in the activities of great apes commented that as intimate contact was observed in a wide range of apes it was logical its origins lie deep in our ancient history, and an analysis of various types of intimate behavior among a broader range of species might push its origins back further still. "Behaviors that we consider as characteristics 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 intimate contact had a social component as it was not common to all societies. "However, as people we thrive or fail on the quality of our emotional bonds, and ways of promoting trust and closeness will have been significant for millions of years," the professor stated. "This could represent an concept that appears a bit incongruous to our misplaced ideas of a rather ruthless and aggressive past, but really it ought to be expected that ancient hominins – and including Neanderthals and our human ancestors collectively – kissed."