Prepare to pucker up for a journey through time. A landmark new study has revealed that the act of kissing is far from a modern human invention, with its origins tracing back a staggering 21.5 million years.
The Ancient Ancestry of a Smooch
Research published in the prestigious journal Evolution and Human Behaviour suggests that our passion for locking lips was likely inherited from our ancient relatives. The study, led by evolutionary biologist Dr Matilda Brindle from the University of Oxford, concludes that the common ancestor of humans, chimpanzees, and bonobos probably enjoyed kissing just as we do today.
"Humans, chimps, and bonobos all kiss," Dr Brindle explained. From this common behaviour, her team deduced that "it's likely that their most recent common ancestor kissed. We think kissing probably evolved around 21.5 million years ago in the large apes."
Saliva Secrets and Neanderthal Affection
The evidence for this ancient intimacy extends even to our extinct cousins, the Neanderthals. Scientists point to a shared oral microbe found in the DNA of both modern humans and Neanderthals as proof of saliva-swapping.
Dr Brindle clarified this fascinating link, stating, "That means that they must have been swapping saliva for hundreds of thousands of years after the two species split." This indicates that Neanderthals, who lived in Eurasia until about 40,000 years ago, may have also been prone to puckering up.
The Puzzling Purpose of a Kiss
For scientists, kissing presents an intriguing biological puzzle. Unlike many behaviours, it offers no clear survival or reproductive advantage. Yet, it is remarkably widespread, observed not only across diverse human cultures but throughout the animal kingdom, from wolves and polar bears to meerkats and giraffes.
So why do we do it? Theories proposed by researchers include:
- A form of social grooming and bonding.
- A method for assessing a mate's compatibility.
- Or perhaps, simply because we—and our animal relatives—enjoy it.
Dr Brindle emphasises that more research is crucial. "It's important for us to understand that this is something we share with our non-human relatives," she said. "We should be studying this behaviour, not just dismissing it as silly because it has romantic connotations in humans."
