🔗 Share this article Neanderthals and Early Humans May Have Engaging in Intimate Contact, Researchers Suggest From seabirds to polar bears, chimpanzees to orangutans, certain species engage in mouth-to-mouth contact. Now, scientists suggest that ancient hominins also engaged in this behavior – and possibly exchanged kisses with modern humans. Shared Oral Evidence It is not the first time scientists have suggested Neanderthals and Homo sapiens were closely connected. Among earlier research, scientists have found humans and their thick-browed cousins shared the identical oral bacteria for hundreds of thousands of years after the two species split, suggesting they exchanged oral fluids. "Probably they were kissing," she said, adding that the concept aligned with studies that has found humans of non-African ancestry have bits of Neanderthal DNA in their genetic makeup, revealing genetic mixing was occurring. Intimate Spin "This offers a different perspective on ancient interactions," the lead researcher said. Writing in the journal Evolution and Human Behavior, the researcher and her team detail how, to explore the historical roots of kissing, they first had to come up with a definition that was not restricted by how humans smooch. Defining Kissing "Previously there were some efforts to define a kiss, but it's very much been focused on humans, which means that essentially other animals don't kiss. Now we know that they probably do, it might just not look from what human kissing resembles," explained the evolutionary biologist. Nonetheless, she said some actions that resembled intimate contact were distinct activities – such as the processing and transfer of food, or "kiss-fighting", observed in aquatic species called certain marine animals. As a result the team developed a description of kissing centered around social behaviors involving intentional mouth-to-mouth contact with a individual of the identical group, with some motion of the mouth but no transfer of nutrition. Study Methods The lead researcher said they focused on accounts of kissing in non-human species from Africa and Asia, including bonobos, apes and great apes, and used digital recordings to confirm the reports. The researchers then integrated this information with information on the genetic connections between extant and ancient types of such primates. Historical Timeline Researchers say the results indicate intimate contact developed approximately 21.5m and 16.9m years ago in the ancestors of the large apes. The position of Neanderthals on this evolutionary lineage suggests it is likely they, too, engaged in a kiss, the scientists say. But the activity might not have been confined to their specific group. "The fact that humans kiss, the reality that we now have shown that Neanderthals very likely engaged, indicates that the two [species] are also likely to have kissed," the researcher added. Evolutionary Importance Although the scientific reasoning is discussed, the expert said intimate contact could be employed in sexual contexts to possibly increase reproductive success or assist in selecting between partners, while it might help strengthen connections when used in a platonic way. Another expert in the behavior of great apes commented that as intimate contact was observed in a broad spectrum of primates it made sense its roots lie deep in our ancient history, and an examination of different forms of kissing among a wider variety of species might extend its beginnings back even earlier still. "Things that we think of as characteristics of human life, like intimate contact, are not unique to us if we look closely at other animals," he said. Social Elements Another professor explained that intimate contact had a cultural element as it was not universal to all societies. "However, as humans we thrive or fail on the strength of our emotional bonds, and methods of promoting confidence and closeness will have been significant for millions of years," she said. "This could represent an concept that appears a bit contradictory to our misplaced ideas of a rather ruthless and aggressive past, but really it should be no surprise that Neanderthals – and even them and our human ancestors together – kissed."