Researchers Discover Kissing Originated 20 Million Years Ago
Kissing, often perceived as a distinctly human behavior, has ancient roots that extend back over 20 million years, according to new research from a team at Oxford University. The study, published in the journal Evolution and Human Behavior, suggests that the behavior likely originated with a common ancestor of modern apes long before the emergence of Homo sapiens.
Researchers conducted an extensive review of decades of studies on various primate species, including chimpanzees, bonobos, orangutans, and gorillas. Utilizing statistical modeling, they estimated that mouth-to-mouth contact first occurred between 16.9 million and 21.5 million years ago, indicating that kissing is not merely a human phenomenon but part of a broader evolutionary narrative.
The Evolutionary Significance of Kissing
The concept of kissing presents what study lead author Matilda Brindle, an evolutionary biologist at Oxford, describes as an “evolutionary conundrum.” While it can facilitate bonding, the behavior carries inherent risks, such as the transmission of germs, which raises questions about its survival advantages. Brindle emphasizes that kissing among primates may serve multiple purposes, though its exact functions remain elusive.
Despite the lack of fossil evidence for kissing, researchers have turned to living species to better comprehend its historical context. The earliest known written references to kissing date back approximately 4,500 years to ancient civilizations in Mesopotamia and Egypt. Interestingly, a 2015 study indicated that only 46% of humans engage in kissing, highlighting the behavior’s variability across cultures.
Brindle notes, “We did find a strong evolutionary signal in kissing, but it doesn’t mean it has to be retained.” She explains that primates exhibit remarkable adaptability and intelligence, suggesting that while kissing may have benefits in certain contexts, it is not universally advantageous. Consequently, if it proves impractical, its risks may outweigh its benefits.
Insights from the Study
The research team ran over 10 million simulations to assess the likelihood of early ape ancestors engaging in kissing. The findings provide strong support for the notion that extinct relatives, such as Neanderthals, may have also practiced kissing. Despite these insights, the study does not clarify the original purpose of kissing or its evolution over time.
Much of the behavioral data relied upon in the research derives from animals in captivity, prompting a call for further investigation into primate behavior in natural environments. Nonetheless, experts recognize the study’s potential to inform future research. Justin Garcia, an evolutionary biologist and director of The Kinsey Institute at Indiana University, commented on the findings, stating, “This is a wonderful example of the interplay of nature and nurture, including for a behavior many of us humans consider so deeply intimate.”
Garcia elaborates on the dual aspects of kissing, noting that it is both a biological and cultural phenomenon. He observes, “Kissing invokes the bodily senses and clearly has some evolutionary origins, but we also know it varies across individuals and populations.”
The research into the origins of kissing opens up avenues for further exploration, potentially shedding light on how human behaviors are shaped by both evolutionary and cultural factors. The implications of this study extend beyond academic interest, as they touch upon fundamental aspects of human interaction and intimacy.
