Scientists believe kissing may have ancient roots, even extending back to Neanderthals. This idea isn’t entirely new. Previous studies have shown that modern humans and Neanderthals shared similar mouth bacteria long after their paths diverged. This suggests they might have swapped saliva, a sign of close contact.
Dr. Matilda Brindle, an evolutionary biologist from the University of Oxford, leads this research. She claims, “They probably were kissing.” This aligns with findings that people of non-African descent carry Neanderthal DNA, hinting at interbreeding between the two groups.
In a recent article published in Evolution and Human Behavior, Brindle and her team worked to define what kissing means outside of human terms. They noticed that previous definitions were very focused on humans. Brindle explained, “Now we know that other animals probably do kiss; it just doesn’t look the same as how we do it.”
Not every mouth-to-mouth interaction counts as kissing. For instance, behaviors like sharing food or “kiss-fighting” seen in fish aren’t quite the same. The researchers opted for a more inclusive definition of kissing, focusing on friendly mouth-to-mouth contact without food transfer.
Their analysis centered on primates like bonobos and chimpanzees, using videos to confirm kissing behaviors. Forking data with evolutionary relationships among primates revealed that kissing likely evolved between 21.5 and 16.9 million years ago in large ape ancestors.
Given Neanderthals’ place in this family tree, the researchers suggest they likely participated in kissing, and not just with their kind. “The fact that we kiss and that Neanderthals likely did too suggests they might have kissed each other,” added Brindle.
While the reasons for kissing are debated, it may help with bonding and mate selection. Dr. Jake Brooker from the University of Durham, who wasn’t part of this study, noted that since kissing is observed in various ape species, it hints that this behavior is deeply rooted in our evolutionary history. He stated, “These behaviors we think are unique to humans are not when we look at other animals.”
Penny Spikins, a professor at the University of York, highlighted the cultural aspect of kissing, emphasizing that it isn’t universal across all societies. However, she pointed out that strong emotional bonds are crucial to human relationships. This suggests that even Neanderthals might have found ways to promote intimacy and trust, which could seem surprising considering their often misunderstood reputation.
In summary, kissing may weave a complex narrative that spans millions of years, connecting us not just to our modern partners but also to our ancient relatives like Neanderthals. It’s a reminder that our shared behaviors with other species can reveal much about our common heritage.
For more on the evolutionary aspects of human behavior, you can check out this Nature article.
