Did Neanderthals and Early Humans Share Affection? Scientists Say Yes

From the majestic Galápagos albatrosses to the playful chimpanzees, many species exhibit behaviors that resemble kissing. A group of researchers now proposes that Neanderthals also engaged in such intimate gestures, and intriguingly, they might have shared kisses with early modern humans.

This isn’t the first time the idea of a close relationship between Neanderthals and early modern humans has been presented. Previous studies have uncovered that these two species, after parting ways, continued to share the same oral microbe for hundreds of thousands of years, a clear indication of saliva exchange.

Dr. Matilda Brindle, an evolutionary biologist and the lead author of the recent study from the University of Oxford, emphasized that while various hypotheses have been suggested in the past, their findings lend credence to a straightforward conclusion: “Probably they were kissing,” she stated. This notion aligns with research indicating that humans of non-African descent carry traces of Neanderthal DNA, hinting at interbreeding events.

“It certainly puts a more romantic spin on human-Neanderthal relations,” Brindle remarked, highlighting the affectionate potential of their interactions.

In their study published in the journal Evolution and Human Behavior, Brindle and her colleagues set out to explore the evolutionary roots of kissing. A significant part of their research involved establishing a broader definition of kissing that extends beyond human practices.

“There have been some previous attempts to define a kiss, but it’s very much been human-centric, which means that basically other animals don’t kiss. Now we know that they probably do; it might just not look exactly like what human kissing looks like,” Brindle explained.

However, the researchers noted that not all behaviors resembling kissing are actually the same. For instance, actions like food chewing and transfer, or the “kiss-fighting” observed in a fish species known as French grunts, represent different forms of interaction.

Consequently, the research team developed a definition of kissing that describes it as friendly interactions involving directed mouth-to-mouth contact between members of the same species, characterized by some mouth movement but no food transfer.

To further understand the dynamics of kissing, the researchers concentrated on documented instances of kissing among primates in Africa and Asia, including bonobos, chimpanzees, and orangutans. They utilized YouTube videos to verify these reports, showcasing the variety of interactions that may qualify as kissing.

By merging this observational data with insights into the evolutionary connections between living and extinct primate species, the researchers were able to trace the origins of kissing. Their findings indicate that this behavior likely evolved between 21.5 million and 16.9 million years ago in the ancestors of large apes.

Given the evolutionary position of Neanderthals within this family tree, the researchers assert that it is plausible they participated in kissing as well. Moreover, they suggest that this behavior may not have been limited to interactions within their own species.

“The fact that humans kiss, and that we now have shown that Neanderthals very likely kissed, indicates that the two [species] are also likely to have kissed,” Brindle added, reinforcing the notion of shared affectionate practices.

The reasons behind this kissing behavior continue to be a topic of debate among scientists. Brindle posits that kissing may serve various evolutionary functions—perhaps enhancing reproductive success in sexual contexts or aiding in mate selection. Additionally, it may play a role in strengthening bonds during platonic interactions.

The intriguing possibility that Neanderthals and early humans may have engaged in kissing not only sheds light on the social behaviors of our ancient relatives but also illustrates the complexity of their relationships. Understanding these interactions provides a richer perspective on the shared heritage of affection that may connect all primate species, including ourselves.