🔗 Share this article Ancient Hominins and Early Humans Were Likely Engaging in Intimate Contact, Scientists Suggest From seabirds to Arctic mammals, primates to great apes, various animals appear to kiss. Currently, scientists suggest that ancient hominins also engaged in this behavior – and possibly locked lips with early Homo sapiens. Common Microbial Evidence It is not the first time scientists have proposed ancient relatives and early modern humans were intimately acquainted. In earlier research, scientists have found modern people and their Neanderthal relatives shared the same mouth microbe for hundreds of thousands of years after the two species split, implying they swapped saliva. "Likely they were engaging in intimate contact," the researcher noted, adding that the idea chimed with studies that has revealed people of certain genetic backgrounds contain Neanderthal DNA in their genetic makeup, demonstrating genetic mixing was occurring. Romantic Interpretation "It certainly puts a more romantic perspective on ancient interactions," Brindle commented. Publishing in the publication a scientific periodical, Brindle and colleagues detail how, to explore the evolutionary origins of intimate contact, they first had to develop a description that was not restricted by how people smooch. Defining Kissing "Previously there were some efforts to describe a kiss, but it's very much been focused on humans, which implies that essentially other animals don't kiss. Currently we know that they probably do, it may appear different from what human kissing looks like," said the evolutionary biologist. Nonetheless, she said some behaviors that looked like intimate contact were something rather different – such as the chewing and food sharing, or "mouth contact", observed in aquatic species known as certain marine animals. Consequently the research group developed a description of kissing centered around friendly interactions involving intentional oral interaction with a individual of the same species, with some movement of the oral area but absence of nutrition. Study Methods The lead researcher said they concentrated on accounts of intimate behavior in non-human species from the African continent and Asia, including bonobos, apes and orangutans, and employed digital recordings to confirm the observations. Scientists then combined this information with information on the evolutionary relationships between living and extinct species of such primates. Historical Origins Researchers propose the results suggest kissing evolved approximately 21.5m 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 likely they, too, indulged in a intimate act, the researchers say. But the behavior may not have been limited to their specific group. "The fact that modern people engage intimately, the fact that we currently have shown that ancient relatives very likely engaged, suggests that the two [species] are also likely to have engage," Brindle noted. Biological Significance While the scientific reasoning is discussed, Brindle said kissing could be used in reproductive situations to potentially increase reproductive success or assist in selecting between partners, while it might help reinforce bonding when practiced in a platonic way. Another expert in the activities of primates commented that as kissing behavior was seen in a broad spectrum of primates it was logical its roots extend far into our evolutionary past, and an analysis of different forms of intimate behavior among a broader range of species might extend its beginnings back further still. "Things that we consider as characteristics of our species, like intimate contact, are not exclusive to us if we look closely at different species," the expert noted. Social Elements Another professor explained that kissing had a social component as it was not common to all human groups. "However, as humans we succeed or struggle on the strength of our emotional bonds, and ways of promoting trust and closeness will have been significant for eons," the professor stated. "This could represent an image that appears a bit contradictory to our misplaced ideas of a rather ruthless and ancient history, but actually it ought to be expected that ancient hominins – and including them and our human ancestors together – kissed."