Neanderthals and Modern Humans Were Likely Kissing, Researchers Propose
Among Galápagos albatrosses to Arctic mammals, primates to orangutans, various animals appear to kiss. Currently, researchers suggest that ancient hominins also engaged in this behavior – and might even have exchanged kisses with modern humans.
Shared Microbial Clues
This isn't the initial instance experts have proposed Neanderthals and Homo sapiens were intimately acquainted. In previous studies, researchers have discovered humans and their thick-browed cousins possessed the same mouth microbe for millions of years after the evolutionary divergence, implying they swapped saliva.
"Likely they were kissing," she said, explaining that the idea chimed with studies that has revealed humans of non-African ancestry contain Neanderthal DNA in their genome, demonstrating interbreeding was at play.
Intimate Interpretation
"It certainly puts a more romantic spin on human-Neanderthal relations," the lead researcher said.
Writing in the publication a scientific periodical, the researcher and colleagues report how, to explore the historical roots of kissing, they first had to come up with a definition that was not restricted by how people smooch.
Describing Intimate Contact
"There have been some previous attempts to define a intimate act, but it's very much been focused on humans, which means that essentially other animals do not engage in this. Now we know that they likely engage, it may appear different from what human kissing looks like," said Brindle.
Nonetheless, she noted some actions that looked like intimate contact were something rather different – such as the processing and transfer of food, or "mouth contact", seen in aquatic species called French grunts.
Consequently the research group came up with a definition of kissing centered around social behaviors involving intentional mouth-to-mouth contact with a member of the same species, with some movement of the mouth but absence of food.
Study Methods
The lead researcher explained they focused on reports of kissing in non-human species from Africa and Asian regions, including primates, apes and orangutans, and used online videos to confirm the reports.
The researchers then integrated this information with information on the genetic connections between extant and ancient types of such animals.
Historical Origins
Researchers say the results indicate intimate contact developed somewhere between 21.5m and 16.9m years ago in the ancestors of the large apes.
Placement of Neanderthals on this family tree suggests it is probable they, too, indulged in a intimate act, the researchers conclude. But the activity may not have been confined to their own species.
"The fact that humans engage intimately, the fact that we now have shown that Neanderthals very likely engaged, indicates that the two [species] are also likely to have engage," the researcher noted.
Evolutionary Significance
Although the evolutionary explanation is discussed, Brindle explained intimate contact could be used in sexual contexts to possibly enhance reproductive success or assist in selecting between partners, while it could assist strengthen connections when used in a platonic way.
Another expert in the behavior of great apes said that as intimate contact was observed in a wide range of apes it was logical its origins extend far into our ancient history, and an analysis of various types of intimate behavior among a broader range of species might push its origins back even earlier still.
"Behaviors that we think of as signatures of our species, like intimate contact, are not unique to us if we examine carefully at different species," he said.
Social Elements
An archaeology expert said that intimate contact had a cultural element as it was not universal to all societies.
"Nonetheless, as humans we thrive or fail on the strength of our emotional bonds, and methods of promoting trust and closeness will have been significant for millions of years," the professor stated. "This could represent an image that appears a bit contradictory to our incorrect assumptions of a supposedly aggressive and ancient history, but really it should be no surprise that Neanderthals – and including Neanderthals and our human ancestors collectively – kissed."
