From Galapagos albatross to polar bears, chimpanzees to orangutans, some species seem to kiss. Now researchers suggest Neanderthals did it too – and perhaps even kissed modern people.
This is not the first time that scientists have suggested that Neanderthals and early modern humans were intimately familiar. Among previous studies, scientists have discovered humans and their thick-browed relatives. we had the same mouth germ for hundreds of thousands of years after the two species split, suggesting they exchanged saliva.
Dr Matilda Brindle, evolutionary biologist and first author of the new study from Oxford Universitysaid that although various theories have been proposed, the new work supports a simple explanation.
“They were probably kissing,” she said, adding that the idea echoes studies that have found people of non-African descent. their genome contains pieces of Neanderthal DNAshowing that interbreeding had taken place.
“It certainly puts a more romantic spin on the human-Neanderthal relationship,” Brindle said.
Letter in the journal “Evolution and Human Behavior”Brindle and his colleagues report that to explore the evolutionary origins of kissing, they first had to come up with a definition that was not limited to how people kiss.
“There have been a few previous attempts to define kissing, but it has been largely human-centric, meaning that basically other animals don't kiss. We now know that they probably kiss, but it may just not look exactly like a human kiss,” Brindle said.
However, she said some behaviors that look like kissing are actually different from each other – such as chewing and passing food or “kiss fighting” seen in fish known as French grunts.
As a result, the team arrived at a definition of kissing based on friendly interactions involving direct mouth-to-mouth contact with a member of the same species, with some mouth movement, but no transfer of food.
Brindle said they focused on reports of kissing primates from Africa and Asia, including bonobos, chimpanzees and orangutans, and used YouTube videos to corroborate the reports.
The researchers then combined this data with information about the evolutionary relationships between living and extinct species of such primates.
The team says the results show that kissing evolved sometime between 21.5 and 16.9 million years ago in the ancestors of great apes.
The Neanderthals' position on this family tree means they probably kissed, too, according to the researchers. But this behavior may not have been limited to members of their own species.
“The fact that humans kiss, the fact that we have now shown that Neanderthals most likely kissed, indicates that these two [species] also probably kissed,” Brindle added.
While an evolutionary explanation is debated, Brindle said kissing can be used in a sexual context to potentially increase reproductive success or aid in choosing between partners, and can also help strengthen a bond if used in a platonic sense.
Dr Jake Brooker, an expert on ape behavior at Durham University who was not involved in the work, said that since kissing behavior has been observed in a wide range of great apes, it makes sense that its origins lie deep in our evolutionary past, and analyzing different forms of kissing across a wider range of species could push its origins back even further.
“What we think of as signs of human life, like kissing, are not unique to us if we look closely at other animals,” he said.
Penny Spikins, professor of archeology of human origins at the University of York, said kissing had a cultural element because it was not common to all societies.
“However, as humans, we thrive or fail on our emotional connections, and ways to build trust and intimacy will be important for millions of years,” she said. “This image may seem a little out of keeping with our misplaced ideas of a rather ruthless and aggressive past, but it's actually not surprising that Neanderthals – and even Neanderthals and our own species together – kissed.”
