🔗 Share this article Neanderthals and Modern Humans Were Likely Kissing, Researchers Propose From Galápagos albatrosses to polar bears, primates to great apes, various animals appear to kiss. Now, researchers propose that Neanderthals also engaged in this behavior – and possibly locked lips with early Homo sapiens. Common Oral Evidence It is not the first time scientists have proposed ancient relatives and early modern humans were intimately acquainted. Among previous studies, researchers have discovered modern people and their thick-browed cousins possessed the identical oral bacteria for millions of years after the evolutionary divergence, suggesting they swapped saliva. "Likely they were kissing," she said, explaining that the concept chimed with studies that has revealed people of non-African ancestry contain ancient genetic material in their genetic makeup, revealing interbreeding was at play. Intimate Spin "It certainly puts a more romantic perspective on ancient interactions," Brindle said. Writing in the journal a scientific periodical, the researcher and her team report how, to investigate the historical roots of kissing, they first had to develop a description that was not restricted by how humans kiss. Defining Kissing "Previously there were some efforts to describe a kiss, but it's largely focused on humans, which implies that essentially other animals do not engage in this. Now we understand that they likely engage, it might just not look from what our intimate contact resembles," explained Brindle. Nonetheless, she said some actions that looked like kissing were something rather different – such as the processing and transfer of food, or "mouth contact", observed in fish known as French grunts. Consequently the research group came up with a description of intimate contact centered around social behaviors involving directed mouth-to-mouth contact with a member of the identical group, with some movement of the oral area but no transfer of food. Research Approach The lead researcher explained they focused on reports of intimate behavior in primates from the African continent and Asia, including bonobos, chimpanzees and great apes, and employed online videos to verify the observations. The researchers then integrated this information with information on the genetic connections between extant and ancient species of such animals. Historical Timeline Researchers say the results suggest kissing evolved approximately 21.5 million and 16.9 million years ago in the predecessors of the large apes. The position of ancient hominins on this evolutionary lineage means it is probable they, too, engaged in a intimate act, the scientists conclude. But the behavior may not have been limited to their own species. "Reality that modern people kiss, the reality that we now have shown that Neanderthals probably engaged, indicates that the two [species] are also likely to have kissed," Brindle added. Evolutionary Importance While the scientific reasoning is debated, Brindle said intimate contact could be used in sexual contexts to possibly enhance mating outcomes or help choose between mates, while it could assist reinforce bonding when used in a non-sexual manner. Another expert in the behavior of primates commented that as kissing behavior was observed in a wide range of apes it made sense its roots extend far into our evolutionary past, and an analysis of different forms of kissing among a wider variety of animals might extend its beginnings back further still. "Behaviors that we consider as characteristics of human life, like intimate contact, are not unique to us if we examine carefully at different species," the expert noted. Social Aspects Another professor explained that kissing had a cultural element as it was not universal to all societies. "Nonetheless, as humans we thrive or fail on the strength of our relationships, and ways of encouraging trust and intimacy 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 supposedly aggressive and aggressive past, but really it should be expected that Neanderthals – and even Neanderthals and our human ancestors together – engaged intimately."