The evolutionary origin of kissing
New research suggests that mouth-to-mouth kissing is a practice far more ancient than we once believed. According to the researchers, this behavior appears to have existed at least 21.5 million years ago, dating back to the common ancestor of humans and great apes. Scientists analyzed large samples of behavior from animals and primates, creating an “evolutionary family tree” to pinpoint when kissing likely first appeared. In the study, kissing was strictly defined as non-aggressive, directed oral contact involving lip movement without the transfer of food. Lead researcher Dr. Matilda Brindle from the University of Oxford notes that humans, chimpanzees, and bonobos share this behavior, suggesting that their common ancestor likely engaged in kissing as well.
Kissing in the animal kingdom and Neanderthals
The study also shows that kissing is not exclusively a human phenomenon. Behaviors fitting the scientific definition were identified in wolves, squirrels, polar bears, and albatrosses. Additionally, there is evidence that Neanderthals also kissed, and the two species—Neanderthals and Homo sapiens—likely exchanged kisses since they shared even common oral bacteria. While the research identifies the “when,” it does not definitively answer the “why.” Among the theories being explored is that kissing emerged from grooming behaviors or that it serves as a means of assessing health and partner compatibility. Dr. Brindle emphasizes that kissing should be studied as a natural evolutionary behavior and not be undervalued due to its human romantic connotations.
Sources BBC News – Report on the study regarding the evolution of kissing – Evolution and Human Behaviour – Scientific journal where the study was published
