Ancient Hominins and Modern Humans Were Likely Kissing, Researchers Propose
From Galápagos albatrosses to Arctic mammals, chimpanzees to orangutans, various animals appear to kiss. Now, scientists propose that ancient hominins did it too – and possibly locked lips with early Homo sapiens.
Shared Oral Evidence
This isn't the initial instance scientists have proposed ancient relatives and early modern humans were closely connected. Among earlier research, researchers have found humans and their thick-browed cousins shared the same mouth microbe for hundreds of thousands of years after the two species split, implying they exchanged oral fluids.
"Likely they were engaging in intimate contact," the researcher noted, adding that the idea aligned with studies that has found people of certain genetic backgrounds contain ancient genetic material in their genome, demonstrating interbreeding was occurring.
Romantic Spin
"This offers a different spin on human-Neanderthal relations," Brindle commented.
Writing in the publication a scientific periodical, Brindle 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 humans smooch.
Describing Kissing
"There have been some efforts to describe a intimate act, but it's very much been focused on humans, which implies that essentially non-human species do not engage in this. Now we understand that they probably do, it may appear different from what human kissing looks like," explained Brindle.
However, she noted some behaviors that resembled intimate contact were distinct activities – such as the processing and transfer of food, or "mouth contact", seen in aquatic species called certain marine animals.
As a result the team developed a description of intimate contact centered around social behaviors involving intentional oral interaction with a individual of the identical group, with some movement of the oral area but no transfer of nutrition.
Research Approach
Brindle explained they concentrated on accounts of intimate behavior in primates from the African continent and Asian regions, including primates, apes and orangutans, and employed digital recordings to verify the observations.
Scientists then integrated this data with information on the evolutionary relationships between extant and ancient species of such animals.
Evolutionary Origins
The team propose the findings suggest kissing evolved somewhere between 21.5m and 16.9 million years ago in the ancestors of the great primates.
Placement of Neanderthals on this family tree means it is probable they, too, indulged in a intimate act, the researchers 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 demonstrated that Neanderthals probably engaged, suggests that the two [species] are also likely to have kissed," the researcher noted.
Biological Significance
Although the evolutionary explanation is discussed, Brindle explained kissing could be employed in reproductive situations to potentially increase mating outcomes or help choose between partners, while it might help strengthen connections when practiced in a platonic way.
Another expert in the activities of primates said that as intimate contact 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 kissing among a broader range of animals might push its origins back even earlier still.
"Behaviors that we consider as characteristics of our species, like intimate contact, are not exclusive to us if we look closely at different species," he said.
Social Aspects
An archaeology expert said that kissing had a cultural element as it was not common to all human groups.
"However, as people we succeed or struggle on the strength of our emotional bonds, and ways of promoting confidence and closeness will have been significant for eons," the professor stated. "This could represent an concept that appears a bit contradictory to our misplaced ideas of a rather ruthless and aggressive past, but actually it should be expected that ancient hominins – and even Neanderthals and our human ancestors collectively – engaged intimately."
