Neanderthals and Early Humans May Have Engaging in Intimate Contact, Scientists Propose
Among Galápagos albatrosses to polar bears, primates to orangutans, various animals appear to kiss. Currently, scientists propose that ancient hominins did it too – and might even have locked lips with early Homo sapiens.
Shared Microbial Clues
This isn't the initial instance scientists have suggested ancient relatives and early modern humans were closely connected. Among previous studies, researchers have found modern people and their thick-browed cousins possessed the same mouth microbe for hundreds of thousands of years after the evolutionary divergence, suggesting they swapped saliva.
"Likely they were kissing," she said, explaining that the idea aligned with studies that has revealed humans of non-African ancestry have bits of Neanderthal DNA in their genetic makeup, revealing interbreeding was at play.
Intimate Interpretation
"It certainly puts a different spin on human-Neanderthal relations," Brindle said.
Writing in the publication a scientific periodical, Brindle and colleagues detail how, to explore the historical roots of kissing, they first had to come up with a definition that was not limited to how humans smooch.
Defining Kissing
"There have been some previous attempts to describe a intimate act, but it's very much been focused on humans, which means that basically non-human species do not engage in this. Now we know that they likely engage, it may appear different from what our intimate contact resembles," said the evolutionary biologist.
However, she said some behaviors that resembled intimate contact were distinct activities – such as the chewing and food sharing, or "mouth contact", seen in aquatic species called French grunts.
As a result the team developed a description of intimate contact based on friendly interactions involving intentional oral interaction with a individual of the same species, with some movement of the oral area but no transfer of nutrition.
Study Approach
Brindle said they concentrated on accounts of kissing in non-human species from Africa and Asian regions, including bonobos, chimpanzees and great apes, and employed online videos to confirm the reports.
Scientists then combined this data with details on the evolutionary relationships between living and extinct types of such animals.
Historical Origins
The team propose the results suggest kissing developed somewhere between 21.5m and 16.9m years ago in the ancestors of the great primates.
Placement of Neanderthals on this evolutionary lineage suggests it is probable they, too, engaged in a intimate act, the researchers conclude. But the behavior may not have been limited to their own species.
"The fact that humans engage intimately, the reality that we now have shown that ancient relatives probably engaged, indicates that the both groups are probably did engage," Brindle added.
Evolutionary Importance
While the scientific reasoning is debated, Brindle explained intimate contact could be used in sexual contexts to possibly enhance mating outcomes or assist in selecting between partners, while it might help strengthen connections when practiced in a non-sexual manner.
A separate researcher in the behavior of great apes said that as kissing behavior was observed in a broad spectrum of primates it made sense its roots lie deep in our ancient history, and an examination of various types of intimate behavior among a broader range of species might push its beginnings back even earlier still.
"Behaviors that we consider as characteristics of our species, like kissing, are not unique to us if we look closely at different species," he said.
Social Elements
Another professor explained that kissing had a cultural element as it was not common to all human groups.
"Nonetheless, as humans we succeed or struggle on the quality of our relationships, and methods of promoting confidence and intimacy will have been important for eons," the professor stated. "It might be an concept that seems a bit incongruous to our incorrect assumptions of a supposedly aggressive and ancient history, but really it ought to be expected that ancient hominins – and including them and our own species together – kissed."
