The microbiome reveals when people first started kissing https://www.welt.de/wissenschaft/article691ece09800234221d23c2dd/der-kuss-in-der-evolution-das-mikrobiom-verraet-wer-den-neandertaler-gekuesst-hat.html Neanderthals & early humans were 'likely to have kissed'. A study (University Oxford) examines the evolutionary origins of kissing and its role in relationships between species https://www.theguardian.com/science/2025/nov/19/neanderthals-early-humans-kissed-research-evolution