🔗 Share this article Neanderthals and Early Humans Were Likely Engaging in Intimate Contact, Scientists Suggest Among seabirds to Arctic mammals, primates to great apes, certain species engage in mouth-to-mouth contact. Currently, scientists suggest that Neanderthals also engaged in this behavior – and might even have exchanged kisses with early Homo sapiens. Common Microbial Clues It is not the first time experts have proposed Neanderthals and early modern humans were intimately acquainted. In earlier research, researchers have found humans and their thick-browed cousins shared the same mouth microbe for millions of years after the evolutionary divergence, implying they swapped saliva. "Likely they were engaging in intimate contact," the researcher noted, explaining that the idea aligned with research that has found people of non-African ancestry have bits of Neanderthal DNA in their genetic makeup, demonstrating genetic mixing was at play. Romantic Spin "This offers a more romantic perspective on ancient interactions," the lead researcher commented. Publishing in the journal a scientific periodical, the researcher and her team detail how, to explore the evolutionary origins of intimate contact, they first had to develop a definition that was not restricted by how people smooch. Describing Kissing "Previously there were some previous attempts to describe a kiss, but it's largely human-centric, which means that basically other animals do not engage in this. Now we know that they probably do, it might just not look from what human kissing resembles," said the evolutionary biologist. However, she said some behaviors that looked like kissing were something rather different – such as the processing and transfer of food, or "mouth contact", observed in aquatic species called certain marine animals. As a result the research group developed a description of kissing based on friendly interactions involving directed mouth-to-mouth contact with a individual of the same species, with some motion of the mouth but no transfer of nutrition. Research Methods The lead researcher explained they focused on reports of intimate behavior in primates from Africa and Asian regions, including primates, apes and orangutans, and used digital recordings to confirm the observations. The researchers then integrated this information with information on the evolutionary relationships between living and extinct species of such primates. Historical Timeline The team say the findings indicate kissing evolved somewhere between 21.5m and 16.9 million years ago in the ancestors of the great primates. Placement of ancient hominins on this family tree means it is likely they, too, indulged in a kiss, the researchers conclude. But the behavior might not have been limited to their own species. "Reality that humans kiss, the fact that we currently have demonstrated that Neanderthals very likely engaged, suggests that the two [species] are also likely to have engage," the researcher noted. Biological Importance Although the scientific reasoning is discussed, Brindle explained intimate contact could be employed in sexual contexts to possibly increase reproductive success or assist in selecting between partners, while it could assist strengthen connections when used in a non-sexual manner. Another expert in the behavior of primates commented that as kissing behavior was seen in a wide range of apes it was logical its roots extend far into our evolutionary past, and an examination of various types of intimate behavior among a broader range of species might push its origins back further still. "Things that we consider as signatures of our species, like kissing, are not unique to us if we examine carefully at other animals," he said. Social Elements An archaeology expert explained that intimate contact had a cultural element as it was not universal to all societies. "However, as people we thrive or fail on the quality of our relationships, and ways of encouraging confidence and intimacy will have been important for millions of years," she said. "It might be an concept that seems a bit incongruous to our incorrect assumptions of a rather ruthless and ancient history, but really it should be expected that ancient hominins – and including Neanderthals and our human ancestors together – engaged intimately."