Kissing Has Been Around for at Least 16 Million Years, Researchers Reveal

It’s Not Just Humans Who Share a Lip‑Lock

Scientists have uncovered evidence that the act of kissing is far older than previously thought. By examining the fossil record and modern animal behavior, researchers estimate that kissing dates back at least 16 million years, predating the emergence of our own species.

The study, published in the journal Evolutionary Biology, combined data from primate field observations with anatomical analyses of extinct mammals. The team found that several lineages—ranging from ancient primates to certain carnivores—displayed mouth‑to‑mouth contact that serves social and reproductive functions.

How Scientists Traced the History of a Kiss

To piece together this timeline, researchers:

• Analyzed the shape of jawbones and dental wear patterns in fossils to infer mouth positioning during social interactions.
• Observed living relatives of extinct species, noting that close‑range lip contact often signals affection, bonding, or mating readiness.
• Cross‑referenced genetic markers linked to oxytocin production, a hormone associated with bonding and the pleasure of kissing.

The convergence of these lines of evidence suggests that the behavior evolved independently in multiple groups, highlighting its deep evolutionary advantage.

Why Kissing Matters in the Animal Kingdom

In many species, mouth‑to‑mouth contact goes beyond simple affection. It can:

• Strengthen social bonds within groups, reducing aggression and fostering cooperation.
• Facilitate mate selection by allowing individuals to assess health and compatibility through scent and taste.
• Serve as a comforting ritual that helps offspring and parents maintain close connections.

These functions mirror the role kissing plays in human societies, where it acts as a signal of intimacy, trust, and emotional closeness.

Implications for Understanding Human Behavior

The discovery reshapes our view of kissing as a uniquely human cultural practice. Instead, it appears to be a deeply rooted biological behavior that has been refined over millions of years. By recognizing its ancient origins, scientists hope to better understand the neurochemical pathways that make kissing such a powerful social tool.

Future research aims to explore how variations of the kiss—such as the “French kiss,” cheek pecks, or nose rubs—evolved across different cultures and species, shedding light on the intricate tapestry of human and animal communication.