🔗 Share this article Ancient Hominins and Modern Humans Were Likely Kissing, Researchers Suggest From Galápagos albatrosses to Arctic mammals, chimpanzees to orangutans, various animals engage in mouth-to-mouth contact. Currently, scientists suggest that Neanderthals did it too – and possibly exchanged kisses with modern humans. Common Oral Evidence This isn't the initial instance scientists have proposed ancient relatives and Homo sapiens were closely connected. Among previous studies, scientists have found modern people and their thick-browed cousins shared the identical oral bacteria for millions of years after the evolutionary divergence, suggesting they exchanged oral fluids. "Probably they were kissing," the researcher noted, adding that the idea aligned with research that has found humans of certain genetic backgrounds contain Neanderthal DNA in their genome, demonstrating interbreeding was occurring. Romantic Interpretation "It certainly puts a different perspective on human-Neanderthal relations," Brindle said. Publishing in the journal Evolution and Human Behavior, Brindle and her team report how, to explore the evolutionary origins of intimate contact, they first had to develop a description that was not limited to how humans kiss. Defining Intimate Contact "There have been some efforts to describe a intimate act, but it's very much been focused on humans, which means that essentially other animals don't kiss. Currently we understand that they probably do, it may appear different from what our intimate contact looks like," said Brindle. However, she said some behaviors that resembled kissing were distinct activities – such as the chewing and food sharing, or "mouth contact", observed in fish known as French grunts. As a result the team came up with a definition of intimate contact centered around social behaviors involving directed mouth-to-mouth contact with a member of the identical group, with some motion of the oral area but no transfer of nutrition. Study Approach Brindle said they concentrated on reports of kissing in primates from the African continent and Asian regions, including bonobos, apes and great apes, and employed digital recordings to verify the reports. Scientists then combined this information with information on the genetic connections between extant and extinct species of such animals. Historical Timeline The team propose the findings suggest kissing evolved somewhere between 21.5 million and 16.9m years ago in the predecessors of the great primates. Placement of Neanderthals on this evolutionary lineage means it is probable they, too, engaged in a intimate act, the scientists say. But the activity might not have been limited to their own species. "Reality that humans engage intimately, the reality that we now have demonstrated that Neanderthals very likely kissed, indicates that the both groups are probably did kissed," Brindle noted. Biological Importance While the evolutionary explanation is debated, Brindle said kissing could be employed in reproductive situations to potentially enhance mating outcomes or help choose between mates, while it might help reinforce bonding when used in a non-sexual manner. Another expert in the behavior of great apes commented that as kissing behavior was seen in a wide range of primates it made sense its roots extend far into our ancient history, and an analysis of different forms of intimate behavior among a broader range of species might push its origins back further still. "Behaviors that we think of as signatures of human life, like intimate contact, are not unique to us if we examine carefully at other animals," he said. Cultural Aspects Another professor explained that kissing had a social component as it was not common to all societies. "However, as people we succeed or struggle on the quality of our emotional bonds, and methods of promoting confidence and closeness will have been important for millions of years," she said. "This could represent an image that seems a bit contradictory to our incorrect assumptions of a rather ruthless and ancient history, but really it should be no surprise that Neanderthals – and even Neanderthals and our human ancestors together – engaged intimately."