🔗 Share this article Neanderthals and Early Humans May Have Engaging in Intimate Contact, Scientists Propose From Galápagos albatrosses to Arctic mammals, chimpanzees to orangutans, certain species appear to kiss. Currently, scientists suggest that ancient hominins also engaged in this behavior – and might even have exchanged kisses with early Homo sapiens. Shared Oral Clues This isn't the initial instance scientists have suggested Neanderthals and Homo sapiens were closely connected. Among previous studies, scientists have discovered humans and their Neanderthal relatives possessed the identical oral bacteria for hundreds of thousands of years after the two species split, suggesting they swapped saliva. "Likely they were engaging in intimate contact," she said, explaining that the idea aligned with studies that has found people of certain genetic backgrounds have bits of Neanderthal DNA in their genome, demonstrating interbreeding was occurring. Intimate Interpretation "This offers a more romantic spin on ancient interactions," Brindle commented. Publishing in the publication Evolution and Human Behavior, the researcher and her team report how, to explore the historical roots of kissing, they first had to come up with a definition that was not restricted by how people kiss. Defining Intimate Contact "Previously there were some previous attempts to describe a kiss, but it's very much been focused on humans, which implies that basically non-human species do not engage in this. Now we understand that they likely engage, it may appear different from what our intimate contact resembles," said the evolutionary biologist. However, she noted some actions that resembled intimate contact were distinct activities – such as the chewing and food sharing, or "mouth contact", observed in fish called French grunts. Consequently the team came up with a definition of kissing centered around social behaviors involving intentional oral interaction with a member of the identical group, with some movement of the mouth but no transfer of food. Research Approach The lead researcher explained they focused on reports of intimate behavior in primates from Africa and Asia, including bonobos, apes and great apes, and used digital recordings to verify the reports. Scientists then integrated this information with details on the genetic connections between living and ancient types of such animals. Evolutionary Origins Researchers say the results indicate kissing developed somewhere between 21.5m and 16.9 million years ago in the ancestors of the large apes. Placement of Neanderthals on this evolutionary lineage means it is probable they, too, indulged in a kiss, the researchers conclude. But the activity may not have been confined to their own species. "Reality that modern people kiss, the fact that we currently have shown that Neanderthals probably engaged, indicates that the two [species] are probably did engage," the researcher noted. Evolutionary Importance Although the scientific reasoning is debated, Brindle said intimate contact could be used in sexual contexts to possibly enhance mating outcomes or help choose between partners, while it could assist strengthen connections when practiced in a non-sexual manner. A separate researcher in the behavior of great apes said that as intimate contact was observed in a broad spectrum of primates it was logical its roots lie deep in our ancient history, and an examination of different forms of intimate behavior among a broader range of animals might extend its origins back further still. "Things that we consider as signatures of our species, like kissing, are not exclusive to us if we look closely at other animals," the expert noted. Social Aspects An archaeology expert explained that intimate contact had a cultural element as it was not common to all societies. "However, as people we succeed or struggle on the strength of our relationships, and methods of encouraging trust and intimacy will have been significant for millions of years," she said. "This could represent an image that seems a bit incongruous to our incorrect assumptions of a supposedly aggressive and aggressive past, but actually it should be no surprise that Neanderthals – and even Neanderthals and our own species collectively – kissed."