Kissing's Ancient Origins Uncovered
Researchers defined kissing as non-aggressive mouth-to-mouth contact without food transfer.
Study reviewed primate literature from Africa, Europe, and Asia.
Bayesian methods and phylogenetic models analyzed ten million simulations for evolutionary estimates.
Neanderthals and humans likely kissed, supported by shared oral microbes and interbreeding.
Lip-touching inherited from large apes but absent in macaques and baboons.
About 46% of cultures engage in kissing, highlighting its variability.