🔗 Share this article Ancient Hominins and Early Humans May Have Engaging in Intimate Contact, Scientists Propose From Galápagos albatrosses to polar bears, primates to great apes, certain species appear to kiss. Currently, scientists suggest that Neanderthals also engaged in this behavior – and possibly locked lips with early Homo sapiens. Shared Oral Clues This isn't the initial instance experts have proposed Neanderthals and early modern humans were intimately acquainted. Among previous studies, researchers have discovered humans and their Neanderthal relatives possessed the identical oral bacteria for millions of years after the two species split, implying they swapped saliva. "Probably they were engaging in intimate contact," the researcher noted, explaining that the idea chimed with studies that has revealed humans of certain genetic backgrounds contain ancient genetic material in their genome, revealing interbreeding was occurring. Intimate Spin "It certainly puts a different spin on ancient interactions," Brindle said. Writing in the journal Evolution and Human Behavior, Brindle and colleagues report how, to investigate the evolutionary origins of intimate contact, they first had to come up with a description that was not restricted by how people kiss. Defining Intimate Contact "There have been some previous attempts to define a intimate act, but it's largely focused on humans, which means that basically non-human species do not engage in this. Now we understand that they likely engage, it may appear different from what our intimate contact resembles," said the evolutionary biologist. Nonetheless, she noted some behaviors that resembled kissing were distinct activities – such as the processing and food sharing, or "mouth contact", seen in fish known as French grunts. Consequently the team came up with a description of kissing based on social behaviors involving intentional mouth-to-mouth contact with a individual of the identical group, with some movement of the oral area but absence of food. Research Approach Brindle said they concentrated on accounts of kissing in primates from Africa and Asia, including primates, apes and great apes, and used digital recordings to confirm the observations. The researchers then combined this data with information on the genetic connections between extant and ancient types of such primates. Evolutionary Timeline The team propose the findings indicate kissing evolved somewhere between 21.5m and 16.9 million years ago in the predecessors of the large apes. Placement of Neanderthals on this family tree suggests it is likely they, too, engaged in a kiss, the scientists conclude. But the activity may not have been confined to their specific group. "Reality that humans kiss, the reality that we now have demonstrated that Neanderthals very likely kissed, suggests that the both groups are also likely to have kissed," the researcher noted. Evolutionary Importance Although the evolutionary explanation is discussed, the expert explained intimate contact could be used in reproductive situations to potentially increase reproductive success or assist in selecting between partners, while it could assist strengthen connections when practiced in a platonic way. Another expert in the behavior of great apes said that as kissing behavior was seen in a wide range of primates it made sense its roots lie deep in our ancient history, and an examination of different forms of intimate behavior among a broader range of animals might push its beginnings back further still. "Behaviors that we consider as signatures of our species, like intimate contact, are not exclusive to us if we examine carefully at other animals," he said. Social Elements Another professor explained that kissing had a social component as it was not universal to all human groups. "Nonetheless, as humans we thrive or fail on the strength of our relationships, and methods of promoting confidence and intimacy will have been important for millions of years," the professor stated. "It might be an concept that appears a bit contradictory to our misplaced ideas of a supposedly aggressive and aggressive past, but really it ought to be expected that ancient hominins – and including Neanderthals and our human ancestors together – kissed."