A KISS THROUGH THE MILLENNIA: An Ancient Ritual Practiced by Our Ancestors
Photo by Emma Fabbri on Unsplash
We kiss all the time… A kiss greets us at birth and accompanies us on our final journey. We kiss our parents and children, siblings, friends, colleagues, husbands, and wives. Yet, not all kisses land on the lips. For instance, we might kiss a child’s scraped knee to comfort them. But why do we do it? Where did one of the most profound symbols of affection in human history come from?
SO MANY TYPES OF KISSES
If we delve into history, we find that the first descriptions of lip-kissing date back to the Bronze Age. These accounts appear on clay tablets from Ancient Mesopotamia and Egypt, dating to around 2500 BCE. By 1500 BCE, records of romantic and sexual kisses began appearing in India, the birthplace of the Kama Sutra.
Over time, kissing evolved into a complex and highly ritualized act. The Romans distinguished three basic types of kisses: osculum, a polite kiss on the cheek symbolizing social affection without romantic undertones; barium, a kiss on the lips representing closer relationships but still devoid of sexual connotation; and savium, a passionate kiss on the lips as an expression of sexual desire.
CULTURAL INFLUENCES
Social, cultural, and gender norms continually shape the practice of kissing. There are significant variations between regions, social groups, and contexts. In parts of Europe, for example, it’s common to greet someone with two cheek-to-cheek kisses, moving left to right.
However, this greeting is typically reserved for women. Men generally shake hands instead. Yet, in specific contexts — such as the initiation of new members into a mafia family — men from the same organization may kiss one another.
Despite such differences, etiquette rules across cultures serve a common purpose: to regulate and moderate the intense intimacy associated with kissing. This suggests that kisses carry a universal, «pre-cultural» biological significance. Their evolutionary roots are much older than any of our cultural conventions.
A KISS WITH A NEANDERTHAL
Kissing wasn’t just practiced by ancient cultures for millennia — it predates civilization itself. Scientific evidence suggests that over 100,000 years ago, Neanderthals and our Cro-Magnon ancestors exchanged saliva and, with it, oral microbes.
But if we look even further into the past, we find that it all may have started much earlier. There are hypotheses that women’s lips evolved as a form of «sexual ornamentation». Some scientists trace the origins of kissing to behaviors such as sniffing, breastfeeding infants, or even parents feeding their offspring pre-chewed food.
However, these theories struggle to align with the presumed evolution of social behavior in great apes in the wild and fail to explain why kissing takes its distinctive form entirely.
HYPOTHESES EXPLAIN MUCH, BUT NOT EVERYTHING
Great apes engage in «mouth-to-mouth» kissing in sexual contexts, seemingly demonstrating continuity with humans. Kissing has also been observed as a form of greeting among chimpanzees. However, this might merely be a romanticized, anthropomorphic projection — similar to the claim that a dog «kisses» its owner by licking their face.
Without addressing the key features of a kiss — lip puckering and the suction-like motion — existing hypotheses cannot fully explain why kissing evolved into its present form instead of something entirely different.
For instance, why don’t humans, like capuchin monkeys, strengthen social bonds by sticking fingers into each other’s eyes and nostrils? The latest hypothesis, published in Evolutionary Anthropology, suggests that kissing originated as a grooming ritual. Dr. Adriano R. Lameira, an evolutionary psychologist from the University of Warwick in the UK, proposed this theory.
TRACES OF AN ANCIENT RITUAL
Dr. Lameira leads a research lab dedicated to exploring the origins of human behavior, cognition, and rituals, including language, dance, music, and imagination. Using modern great apes as models for ancient hominins, he builds theories on the evolution of human behaviors.
Based on his knowledge of primate behavior, Lameira suggests that kissing is a modified form of grooming — a ritual for maintaining fur. At the end of such grooming sessions, the groomer puckers their lips as if to kiss. In reality, they are extending their lips to pick up debris, dead skin, or parasites.
As humans lost much of their body hair over evolutionary time, the hygienic importance of grooming diminished. However, it didn’t disappear entirely and persisted in the form of kissing. Compared to typical primates, modern humans engage in self-grooming 89% less than expected, particularly for hygienic purposes.
Thus, our kiss is essentially a relic of ancestral grooming behavior, originally used to signal and strengthen social and familial bonds.
FROM KISSES TO SPEECH!
The decisive moment in the evolution of kissing came when our ancestors transitioned to a terrestrial lifestyle. On the ground, parasitic exposure is higher, making self-care far more critical for terrestrial apes than for arboreal ones. This suggests that kissing could only have developed after our ancestors descended from the trees — around 7 million years ago.
Millions of years later, as we began losing our fur, grooming became obsolete as a hygienic function. Yet, to express affection, our species preserved this behavior in a symbolic, crystallized form — the kiss.
This means kissing is likely one of the oldest human rituals, continuously practiced for millions of years! Furthermore, some researchers argue that the function of «tactile grooming» was replaced by «vocal grooming» — vocal exchanges that eventually led to the evolution of human speech.
Original Research:
- Neanderthal tooth plaque hints at meals — and kisses
- The evolutionary origin of human kissing
- The ancient history of kissing
- Did the human kiss begin as an ape grooming ritual?
