🔗 Share this article Neanderthals and Early Humans Were Likely Kissing, Scientists Suggest From Galápagos albatrosses to polar bears, primates to great apes, certain species engage in mouth-to-mouth contact. Now, scientists propose that Neanderthals did it too – and might even have locked lips with modern humans. Shared Microbial Evidence It is not the first time experts have proposed Neanderthals and early modern humans were intimately acquainted. In previous studies, researchers have discovered humans and their Neanderthal relatives possessed the identical oral bacteria for hundreds of thousands of years after the evolutionary divergence, implying they exchanged oral fluids. "Probably they were kissing," the researcher noted, adding that the concept chimed with studies that has found humans of non-African ancestry contain Neanderthal DNA in their genome, demonstrating genetic mixing was occurring. Intimate Spin "It certainly puts a different perspective on human-Neanderthal relations," the lead researcher commented. Publishing in the journal Evolution and Human Behavior, the researcher and colleagues detail how, to explore the historical roots of intimate contact, they first had to come up with a description that was not restricted by how people kiss. Describing Kissing "There have been some previous attempts to define a intimate act, but it's largely focused on humans, which means that essentially non-human species don't kiss. Now we understand that they probably do, it might just not look from what human kissing looks like," explained the evolutionary biologist. Nonetheless, she said some actions that resembled intimate contact were distinct activities – such as the processing and food sharing, or "kiss-fighting", seen in aquatic species called certain marine animals. Consequently the team came up with a definition of kissing based on friendly interactions involving directed mouth-to-mouth contact with a member of the same species, with some motion of the oral area but no transfer of food. Study Methods The lead researcher said they concentrated on accounts of kissing in non-human species from the African continent and Asian regions, including primates, apes and orangutans, and used digital recordings to verify the observations. Scientists then combined this data with information on the genetic connections between extant and ancient types of such primates. Evolutionary Origins The team say the findings indicate intimate contact evolved approximately 21.5 million and 16.9m years ago in the predecessors of the large apes. Placement of Neanderthals on this family tree suggests it is probable they, too, engaged in a intimate act, the researchers say. But the behavior may not have been confined to their specific group. "Reality that humans kiss, the reality that we now have demonstrated that ancient relatives probably kissed, indicates that the two [species] are also likely to have kissed," Brindle added. Evolutionary Importance Although the scientific reasoning is discussed, Brindle explained kissing could be employed in sexual contexts to possibly increase reproductive success or assist in selecting between partners, while it might help reinforce bonding when practiced in a platonic way. A separate researcher in the behavior of primates said that as kissing behavior was seen in a broad spectrum of primates it made sense its roots lie deep in our evolutionary past, and an analysis of different forms of kissing among a wider variety of species might push its beginnings back further still. "Things that we think of as signatures of human life, like kissing, are not exclusive to us if we examine carefully at other animals," he said. Social Aspects An archaeology expert explained that kissing had a cultural element as it was not common to all human groups. "However, as humans we succeed or struggle on the quality of our relationships, and methods of encouraging trust and closeness will have been important for millions of years," the professor stated. "This could represent an concept that seems a bit contradictory to our misplaced ideas of a supposedly aggressive and aggressive past, but actually it should be expected that Neanderthals – and even Neanderthals and our human ancestors together – kissed."