🔗 Share this article Ancient Hominins and Early Humans Were Likely Engaging in Intimate Contact, Researchers Propose Among Galápagos albatrosses to polar bears, primates to great apes, various animals engage in mouth-to-mouth contact. Currently, scientists propose that ancient hominins also engaged in this behavior – and might even have exchanged kisses with early Homo sapiens. Shared Microbial Clues It is not the first time experts have suggested Neanderthals and Homo sapiens were closely connected. In earlier research, scientists have found humans and their thick-browed cousins shared the same mouth microbe for millions of years after the evolutionary divergence, suggesting they swapped saliva. "Likely they were engaging in intimate contact," the researcher noted, explaining that the idea chimed with research that has found people of certain genetic backgrounds have bits of Neanderthal DNA in their genome, demonstrating genetic mixing was occurring. Intimate Spin "It certainly puts a more romantic perspective on ancient interactions," the lead researcher commented. Writing in the journal a scientific periodical, the researcher and colleagues detail how, to investigate the evolutionary origins of kissing, they first had to come up with a definition that was not limited to how people smooch. Describing Kissing "Previously there were some previous attempts to define a kiss, but it's largely human-centric, which implies that essentially non-human species don't kiss. Now we understand that they probably do, it may appear different from what our intimate contact resembles," explained the evolutionary biologist. However, she said some behaviors that looked like kissing were distinct activities – such as the chewing and food sharing, or "mouth contact", seen in fish known as certain marine animals. Consequently the research group came up with a definition of intimate contact centered around social behaviors involving intentional oral interaction with a individual of the same species, with some motion of the mouth but no transfer of food. Research Methods The lead researcher said they focused on reports of kissing in non-human species from the African continent and Asia, including bonobos, chimpanzees and great apes, and employed online videos to verify the observations. The researchers then combined this information with information on the evolutionary relationships between extant and ancient types of such primates. Evolutionary Origins The team propose the results indicate kissing evolved approximately 21.5 million and 16.9 million years ago in the ancestors of the great primates. The position of ancient hominins on this evolutionary lineage means it is probable they, too, engaged in a kiss, the researchers conclude. But the activity might not have been confined to their specific group. "The fact that humans kiss, the reality that we now have demonstrated that Neanderthals probably kissed, indicates that the two [species] are probably did engage," the researcher noted. Evolutionary Importance While the scientific reasoning is discussed, the expert said kissing could be used in sexual contexts to possibly increase mating outcomes or help choose between mates, while it could assist reinforce bonding when used in a platonic way. A separate researcher in the activities of primates said that as intimate contact was seen in a wide range of apes it made sense its roots extend far into our evolutionary past, and an analysis of various types of intimate behavior among a broader range of species might push its beginnings back further still. "Behaviors that we think of as signatures of our species, like intimate contact, are not exclusive to us if we look closely at other animals," the expert noted. Cultural Elements An archaeology expert said that kissing had a social component as it was not universal to all societies. "Nonetheless, as people we succeed or struggle on the strength of our relationships, and ways of encouraging trust and intimacy will have been important for eons," she said. "It might be an concept that appears a bit incongruous to our incorrect assumptions of a supposedly aggressive and aggressive past, but really it ought to be expected that Neanderthals – and even Neanderthals and our own species collectively – kissed."