🌅 Kissing Is an Ancient Trait

SOURCE

Brindle et al. (2025)

WHAT TO KNOW

• Researchers at Oxford University in the U.K. found kissing likely evolved in a common human ancestor that lived around 21.5-16.9 million years ago, long before modern humans existed. The new study suggests kissing is an ancient trait common to large apes and ancient humans, and was retained throughout the course of evolution to persist among most large apes today, including modern humans. The study also found our extinct human relatives, Neanderthals, probably engaged in kissing, and that modern humans and Neanderthals likely kissed one another.

WHY IT MATTERS

• Scientists have long known that kissing occurs in a number of different animals, however, the act is also somewhat of an evolutionary paradox as it carries no obvious reproductive or survival advantage and may actually be risky, since it carries the chance of disease transmission. The present study is the first to examine kissing under an evolutionary lens, and the authors say their work is the first step in addressing whether kissing is an evolved behavior or cultural invention.

CONNECT THE DOTS

• The present study helps uncover the evolutionary timeline of kissing, however, researchers today still can’t answer why humans and other animals do it. Further, while kissing may seem commonplace nowadays, the act is present in just 46% of documented human cultures, seemingly underscoring its lack of importance to mating and/or reproductive success.