THEThe first kiss is never forgotten, even if it happened 21 million years ago. According to a study published in the journal Evolution and Human Behavior and coordinated byUniversity of Oxford, the most romantic gesture in the world has very ancient origins. They were the great apes to give the first kiss in the history of humanity. And not only that: also i Neanderthalour extinct “cousins”, probably exchanged kisses.
What is meant by kiss?
According to the study, kissing is non-aggressive mouth-to-mouth contact between individuals of the same speciesaccompanied by movements of the lips or oral parts, without transfer of food. Behaviors such as exchanging food, “fighting kisses” or licking between different species are therefore excludedlike that of dogs towards their owners.
Kisses between Neanderthals and early humans
The researchers analyzed behavioral data from modern primates — chimpanzees, bonobos, orangutans — widespread in Africa, Europe and Asia. The study shows that kissing evolved between 21.5 and 16.9 million years ago in the common ancestor of great apes. But not only that: Neanderthals probably exchanged kisses with each other and also with early modern humans. This detail ties in with other research that humans and Neanderthals shared oral microbes and genetic material via saliva.
Evolutionary behavior or cultural invention?
The main thrust of the research is to show that kissing has a long evolutionary history. It is not just a romantic or cultural gesture, but also a window into the social and sexual evolution of primates. «Although this may seem like ordinary or universal behavior, it is documented in only 46% of human cultures»remember Catherine Talbotamong the authors of the study. “Social norms and context vary greatly between societies, raising the question of whether kissing is an evolved behavior or a cultural invention. This is the first step to address the issue.”.
Why kiss?
We thus speak of a sort of evolutionary paradox of the kiss: Despite risks, such as the transmission of disease via saliva, and the absence of a direct reproductive benefit, kissing has survived and spread over the millennia. Studies suggest possible sexual and emotional functions, such as the evaluation of the quality of the partner, the regulation of social tensions or the transmission of beneficial microbes.
Towards new research to understand the origin of the kiss
According to the authors, the work constitutes a starting point for future comparative investigations on the evolution of kissing. Scholars suggest including the kiss in the ethological observations of sexual behaviors, documenting the age, sex, social status, environment and context (sexual or emotional) of the subjects observed. Furthermore, targeted experiments could evaluate the costs and benefits of kissing in different species. As the study points out, the kiss could be much more than «a little trick of nature to keep quiet when words become superfluous». It could instead be a complex evolutionary behaviordeeply rooted in the history of primates and, surprisingly, also of Neanderthals.
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