🔗 Share this article Ancient Hominins and Modern Humans May Have Kissing, Researchers Propose From seabirds to polar bears, primates to orangutans, certain species engage in mouth-to-mouth contact. Now, researchers propose that Neanderthals did it too – and possibly exchanged kisses with modern humans. Common Microbial Evidence It is not the first time scientists have suggested Neanderthals and early modern humans were intimately acquainted. In earlier research, scientists have discovered modern people and their Neanderthal relatives shared the same mouth microbe for millions of years after the evolutionary divergence, suggesting they swapped saliva. "Probably they were engaging in intimate contact," the researcher noted, adding that the concept chimed with studies that has revealed humans of non-African ancestry have bits of ancient genetic material in their genetic makeup, revealing interbreeding was occurring. Romantic Spin "This offers a more romantic spin on human-Neanderthal relations," the lead researcher said. Writing in the journal Evolution and Human Behavior, Brindle and her team 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 smooch. Defining Intimate Contact "Previously there were some previous attempts to describe a intimate act, but it's largely focused on humans, which means that essentially non-human species do not engage in this. Now we know that they probably do, it may appear different from what human kissing resembles," explained the evolutionary biologist. However, she noted some behaviors that resembled intimate contact were something rather different – such as the processing and transfer of food, or "mouth contact", observed in aquatic species known as certain marine animals. Consequently the research group developed a description of kissing centered around social behaviors involving intentional mouth-to-mouth contact with a member of the identical group, with some motion of the oral area but absence of nutrition. Study Methods Brindle explained they concentrated on reports of intimate behavior in primates from the African continent and Asian regions, including bonobos, chimpanzees and orangutans, and used digital recordings to confirm the reports. The researchers then combined this information with information on the evolutionary relationships between living and ancient types of such animals. Historical Timeline Researchers say the results indicate kissing evolved somewhere between 21.5 million and 16.9m years ago in the ancestors of the large apes. The position of ancient hominins on this family tree means it is probable they, too, engaged in a intimate act, the scientists say. But the behavior might not have been confined to their specific group. "The fact that modern people kiss, the reality that we currently have demonstrated that ancient relatives probably engaged, indicates that the two [species] are probably did engage," Brindle noted. Evolutionary Significance While the evolutionary explanation is debated, Brindle explained kissing could be employed in sexual contexts to potentially 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 primates commented that as kissing behavior was observed in a broad spectrum of primates it was logical its origins lie deep in our ancient history, and an analysis of different forms of kissing among a wider variety of species might extend its origins back even earlier still. "Behaviors that we think of as signatures of human life, like kissing, are not unique to us if we look closely at different species," he said. Cultural Elements An archaeology expert said that intimate contact had a social component as it was not universal to all human groups. "However, as humans we succeed or struggle on the quality of our relationships, and ways of promoting trust and intimacy will have been important for millions of years," the professor stated. "This could represent an image that appears a bit contradictory to our misplaced ideas of a rather ruthless and ancient history, but really it should be expected that ancient hominins – and even them and our human ancestors collectively – engaged intimately."