Kissing is one of those human activities that seems perfectly normal until someone describes it without the romantic filter. Two people bring their faces together, press their lips against each other, sometimes exchange saliva, and their brains interpret the whole experience as pleasurable. Viewed this way, the question of who first decided that we should “eat” each other suddenly does not sound silly at all.
Kissing was probably not invented by any particular person. Written evidence of romantic kissing dates back about 4,500 years to the ancient Near East, but the behavior itself may be dramatically older. Evolutionary research published in 2026 even suggests that something resembling a kiss may have existed among the common ancestors of the great apes around 17 to 21 million years ago.
Who invented kissing?
The most accurate answer is a little disappointing: we do not know, and probably never will.
There is no known “inventor of the kiss” whom we can credit with deciding to put their mouth on someone else’s and then convincing the rest of humanity that it was a good idea. Kissing is much more likely to be a behavior that developed gradually and acquired different social, familial and romantic meanings over thousands of years.
There is also a fundamental problem with tracing its origins: a kiss leaves no fossil. Archaeologists can discover stone tools, bones, hearth remains or traces of food that are hundreds of thousands of years old, but two people who kissed 100,000 years ago left behind no unambiguous archaeological evidence of it.
Scientists therefore piece together the history of kissing from several sources. They draw on ancient texts, anthropological data from different cultures, observations of primate behavior and evolutionary models that can help estimate whether our very distant ancestors already engaged in similar behavior.
The oldest known kisses date back more than 4,500 years
In the past, the origins of romantic kissing were often linked to ancient India and texts dating from around the second millennium BCE. More recent analysis of historical sources, however, shows that kissing appeared considerably earlier in Mesopotamia, roughly the territory of present-day Iraq and Syria.
Cuneiform texts show evidence of kissing as early as the third millennium BCE. Research into ancient sources describes evidence from around the middle of the third millennium BCE and shows that kissing had several meanings. It occurred between lovers, but also among family members and friends, and could express respect or social status. (ScienceDirect)
This matters because kissing does not appear in these texts as some new or exotic practice that needed to be explained to readers. It is simply part of the stories and social life. It is therefore reasonable to assume that people were already kissing before the earliest surviving texts were written.
The first recorded kiss was not the first kiss in history
The earliest evidence of an activity should not be confused with the moment it originated. If archaeologists thousands of years from now found the oldest surviving photograph of someone riding a bicycle and it dated from 1950, that would not mean cycling began in 1950.
This problem is even more pronounced with kissing. Homo sapiens existed long before writing, and our ancestors lived for millions of years before us. If they kissed, they had no way to write a report about it.
According to current research, it is entirely possible that the origins of kissing predate the emergence of modern humans.
Kissing may be older than humanity
In January 2026, the journal Evolution and Human Behavior published a study that attempted to reconstruct the evolutionary history of kissing among primates.
The scientists first needed to develop a definition that could also be applied to animals. They defined a kiss as non-aggressive mouth-to-mouth contact between two members of the same species involving some movement of the lips or mouth, without the transfer of food.
They then collected observations of various primates and used phylogenetic methods to investigate when such behavior might have emerged among their common ancestors.
The result pushes the possible origins of kissing back to a period almost unimaginably remote compared with ancient Mesopotamia. According to the model, kissing may already have existed in the common ancestor of today’s great apes approximately 21.5 to 16.9 million years ago. (ScienceDirect)
If this evolutionary reconstruction is correct, humans probably did not invent kissing. Instead, we inherited the foundations of a behavior that had existed for millions of years before us.
Neanderthals probably kissed too
The same study concluded that Neanderthals probably also engaged in kissing.
Of course, this does not mean scientists found a fossil of two Neanderthals caught in the act. It is an evolutionary reconstruction based on relationships among species and behavior that can be observed in living primates.
We therefore cannot say how often Neanderthals kissed, whom they kissed or whether they attached a romantic meaning to it comparable to ours. What matters is the likelihood that behavior based on mouth-to-mouth contact was already part of their social repertoire.
Chimpanzees and other apes kiss too
Humans are not the only primates that display behavior resembling kissing. Mouth-to-mouth contact also occurs among some other great apes.
However, we should not automatically imagine an animal version of a romantic movie kiss. Among primates, mouth-to-mouth contact can serve purposes such as reinforcing social bonds or reconciling after conflict.
The existence of similar behavior in several related species is one reason scientists doubt the idea that kissing arose as a one-off human cultural invention.
In other words, the question “Who was the first person to think of kissing?” may be fundamentally misguided. By the time the first Homo sapiens kissed another Homo sapiens, our evolutionary ancestors may already have been doing something similar for a very, very long time.
But why did they start kissing with their mouths?
This brings us to the biggest mystery.
We can express social closeness in many ways. We hug, touch each other with our hands, stroke one another or simply remain close together. Why did the lips in particular become so important?
There is no definitive answer yet. However, one recent hypothesis offers a rather interesting explanation.
It may have started with grooming
Primates spend a great deal of time grooming one another. This is not merely about removing dirt, dead skin or parasites. Grooming is also an important social behavior that helps create and maintain relationships.
In 2024, Adriano Lameira of the University of Warwick proposed a hypothesis known as the “groomer’s final kiss.” According to this idea, the human kiss may be a distant remnant of the final stage of grooming among our primate ancestors.
At the end of a thorough grooming session, a primate may have used its lips and gentle suction to remove dirt or a parasite from fur or skin. As our ancestors lost most of their thick body hair over the course of evolution, the need for such prolonged grooming diminished considerably.
Its social function, however, may have survived.
According to the hypothesis, the entire ritual gradually became shorter until all that remained was brief contact with the lips, no longer used for hygiene but to signal closeness and trust. (PubMed Central (PMC))
It sounds a little like an evolutionary process in which, after millions of years, we discard the entire original routine but keep the final step because we have grown fond of it.
Has this theory been proven?
No.
It is a scientific hypothesis that attempts to explain the origins of the behavior based on what we know about primate social life. The first kiss cannot be reconstructed after the fact, and we will probably never have a single theory that can be considered definitively proven.
Other explanations have also been proposed, including a link between kissing and passing pre-chewed food to infants by mouth. More recent evolutionary research, however, suggests that the full story may be far more complicated and that kissing need not have arisen from one specific behavior alone.
Why did kissing persist once we no longer needed to groom fur?
Even if kissing originated in entirely practical behavior, its hygienic function is clearly absent among people today. Nevertheless, it has become one of the most powerful expressions of intimacy in many societies.
One possible reason is the sensitivity of the lips themselves. They contain many nerve endings, and contact between them gives the brain intense tactile stimulation. When faces come close together, we also receive information through touch, smell and taste.
A kiss can also serve as a very powerful social signal. Allowing another person to come within a few centimeters of your face and engage in such intimate contact requires a certain degree of trust. Depending on the situation, the same gesture can therefore signify romantic interest, affection, sexual intimacy, friendship or a family bond.
Evolution does not require a behavior to have only one function. If it is pleasurable, helps build relationships and also provides information about another person, it can persist long after its original purpose has disappeared.
Not everyone engages in romantic kissing
Perhaps the biggest problem with the simple theory that romantic kissing is automatically programmed into every human being is the fact that it is not universal.
A study published in American Anthropologist in 2015 examined 168 cultures. It found evidence of romantic-sexual kissing in only 46% of them. In the remaining 54%, researchers did not record romantic kissing as a traditional behavior. (AnthroSource)
That is a fairly significant finding. If romantic kissing were an absolutely essential biological behavior among modern humans, we would expect to find it virtually everywhere.
Instead, kissing appears to involve an interaction between biology and culture. Humans may have very ancient biological predispositions toward close contact and touching with the mouth, but the specific rules governing whom to kiss, where to kiss them and what a particular kiss means are largely social.
In some cultures, our romantic kiss would simply seem strange
What we take for granted as romantic may not seem natural to everyone on the planet.
Different societies have developed their own ways of expressing affection and intimacy. In some places, kissing on the lips is a common romantic gesture; elsewhere, it may historically have played no role in courtship at all.
It is therefore possible that basic kiss-like behavior is very old, while the romantic kiss as we know it from modern European or American films is a combination of evolutionary predispositions and culturally learned behavior.
Why does exchanging saliva not disgust us?
From a biological perspective, there is another interesting aspect of kissing. The human mouth is full of microorganisms, and kissing involves exchanging saliva. In most other circumstances, the prospect of someone else’s saliva in our mouth would hardly rank among the day’s most appealing offers.
When it involves someone we are attracted to, however, the brain evaluates the situation very differently.
This clearly demonstrates how powerfully social context can alter our perception. Contact that would seem repulsive coming from a stranger can become an expression of trust and intimacy with a partner.
It is therefore not so strange that human culture has managed to turn an activity that objectively involves contact between mucous membranes and saliva into one of the best-known symbols of romance.
So who decided that we should “devour” each other?
Most likely, no one in particular.
Current evidence points instead to gradual development. Kiss-like behavior may date back millions of years and may originally have had nothing to do with romance. It could have helped with social contact, mutual care or strengthening relationships.
At some point during evolution, it may have become a form of close contact that humans then began to use between partners as well. Individual cultures subsequently assigned their own rules and meanings to kissing.
So no prehistoric human probably woke up one morning, looked at their partner and thought: “Today I’ll try putting my mouth on theirs and see what happens.”
If recent evolutionary studies are correct, their ancestors may have been doing it millions of years earlier.
Why people kiss: video
In a short video, BBC Ideas explores why we kiss, where the behavior may have come from and why it is not the same in every culture.
Kissing may be much older than we thought
We will almost certainly never know about the first kiss in history. The earliest written records merely prove that kissing was already known in some ancient societies approximately 4,500 years ago. They do not tell us when it actually began.
When we combine historical records with the behavior of other primates and modern evolutionary models, a far more interesting picture emerges. Kissing may not be a human invention only a few thousand years old. Its roots could stretch back tens of millions of years.
And so one of the most romantic activities practiced by modern humans may have begun as an entirely practical part of caring for the bodies of our furry ancestors. Evolution sometimes has a strange sense of humor.
Sources
- Troels Pank Arbøll, Sophie Lund Rasmussen – Ancient kiss-tory: new perspectives on the evolution of early historical kissing, Evolution and Human Behavior, 2025. (ScienceDirect)
https://www.sciencedirect.com/science/article/pii/S1090513825001278 - Matilda Brindle et al. – A comparative approach to the evolution of kissing, Evolution and Human Behavior, 2026. (ScienceDirect)
https://www.sciencedirect.com/science/article/pii/S1090513825001370 - Adriano R. Lameira – The evolutionary origin of human kissing, Evolutionary Anthropology, 2024. (PubMed Central (PMC))
https://pmc.ncbi.nlm.nih.gov/articles/PMC11624293/ - William R. Jankowiak, Shelly L. Volsche, Justin R. Garcia – Is the Romantic–Sexual Kiss a Near Human Universal?, American Anthropologist, 2015. (AnthroSource)
https://anthrosource.onlinelibrary.wiley.com/doi/full/10.1111/aman.12286
Robert
I’m interested in technology and history, especially true crime stories. For three years I ran a fact-based portal about modern history, and for a year I co-built a blogging platform where I published dozens of analytical articles. I founded offpitch so that quality content wouldn’t be hidden behind a paywall.
