Presented as the first work dedicated to the evolutionary history of kissing, the study analyzed behavioral data from primates – such as chimpanzees, bonobos and orangutans – that make contact non-aggressive word of mouth no food transfer. From the phylogenetic tree of primates, researchers estimated that this behavior was already present in the common ancestor of great apes, appearing among 16.9 and 21.5 million years.
“Kissing has persisted throughout evolution and remains in most great apes,” says the team. The investigation also shows that the Neanderthals – which coexisted with Homo sapiens until around 40,000 years ago – “probably also kissed”, reinforcing previous evidence of sharing of oral microbes and genetic material between both species.
By combining evolutionary biology with behavioral observation, “we were able to draw conclusions about traits that do not leave fossils, such as kissing”, highlights Stuart West, co-author of the study. For the main researcher, Matilda Brindle, the results reveal “the remarkable diversity of sexual behaviors of our primate cousins”.