🔗 Share this article Ancient Hominins and Modern Humans Were Likely Engaging in Intimate Contact, Researchers Propose From seabirds to polar bears, primates to orangutans, certain species engage in mouth-to-mouth contact. Now, scientists suggest that ancient hominins did it too – and possibly exchanged kisses with early Homo sapiens. Common Microbial Evidence This isn't the initial instance scientists have suggested ancient relatives and early modern humans were closely connected. In previous studies, scientists have discovered humans and their Neanderthal relatives possessed the same mouth microbe for hundreds of thousands of years after the evolutionary divergence, implying they exchanged oral fluids. "Probably they were kissing," she said, adding that the idea chimed with studies that has found people of non-African ancestry have bits of Neanderthal DNA in their genome, revealing genetic mixing was at play. Intimate Spin "It certainly puts a more romantic spin on human-Neanderthal relations," the lead researcher commented. Publishing in the journal a scientific periodical, the researcher and colleagues report how, to investigate the evolutionary origins of kissing, they first had to develop a description that was not limited to how people kiss. Describing Kissing "There have been some previous attempts to describe a intimate act, but it's very much been human-centric, which means that essentially non-human species do not engage in this. Now we understand that they likely engage, it may appear different from what human kissing looks like," said the evolutionary biologist. However, she noted some actions that looked like kissing were distinct activities – such as the processing and food sharing, or "mouth contact", seen in aquatic species called French grunts. As a result the team developed a definition of intimate contact based on social behaviors involving intentional oral interaction with a member of the same species, with some motion of the oral area but absence of food. Study Approach Brindle explained they concentrated on reports of intimate behavior in primates from Africa and Asian regions, including bonobos, chimpanzees and orangutans, and employed online videos to verify the observations. The researchers then combined this information with information on the genetic connections between extant and extinct species of such animals. Evolutionary Origins The team say the results indicate kissing evolved somewhere between 21.5m and 16.9 million years ago in the ancestors of the large apes. Placement of Neanderthals on this evolutionary lineage means it is probable they, too, engaged in a intimate act, the scientists say. But the behavior may not have been limited to their specific group. "Reality that modern people engage intimately, the reality that we now have shown that ancient relatives probably kissed, indicates that the two [species] are probably did kissed," the researcher added. Biological Significance Although the evolutionary explanation is discussed, the expert explained kissing could be used in reproductive situations to potentially enhance mating outcomes or assist in selecting between partners, while it might help strengthen connections when practiced in a platonic way. A separate researcher in the behavior of great apes said that as intimate contact was observed in a broad spectrum of primates it made sense its origins extend far into our ancient history, and an analysis of various types of kissing among a broader range of species might extend its origins back even earlier still. "Behaviors that we think of as signatures of our species, like kissing, are not unique to us if we look closely at other animals," the expert noted. Cultural Elements Another professor explained that kissing had a cultural element as it was not universal to all societies. "However, as humans we succeed or struggle on the strength of our relationships, and methods of encouraging trust and intimacy will have been important for eons," the professor stated. "It might be an image that seems a bit contradictory to our incorrect assumptions of a rather ruthless and aggressive past, but actually it should be no surprise that Neanderthals – and even them and our human ancestors together – engaged intimately."