What's happened
New research traces kissing back 16-21 million years, showing it was common among large apes and Neanderthals. The behavior, which offers no clear survival benefit, may have evolved as a sign of affection and trust, with saliva transfer evidence linking humans and Neanderthals. The study broadens understanding of this universal act.
What's behind the headline?
The discovery that kissing dates back over 20 million years challenges the notion that it is merely a cultural or romantic act. Instead, it appears to be an ancient behavior linked to social bonding and trust. The fact that kissing is observed in diverse species—from primates to birds and marine mammals—indicates it may serve fundamental social functions beyond reproduction.
This research underscores that behaviors like kissing, despite their risks such as disease transmission, have persisted because they foster social cohesion. The evidence of saliva exchange between humans and Neanderthals suggests that this behavior was not solely human but shared with our closest relatives, hinting at its importance in early social interactions.
The findings also raise questions about the evolution of human intimacy and whether kissing's primary role was social bonding rather than sexual. Future research could explore how cultural norms influence the expression of this behavior today, and whether its origins continue to shape human relationships.
What the papers say
The Independent reports that kissing may have evolved between 16 and 21 million years ago, with evidence from saliva transfer and behavior analysis suggesting Neanderthals also engaged in kissing. The study, led by Oxford University, highlights the behavior's ancient roots and its presence across many species.
The New York Times emphasizes the surprising diversity of kissing behaviors among animals, including insects and marine mammals, and notes that it is more widespread than previously thought. Dr. Brindle from Oxford points out that kissing's evolutionary mystery is linked to its minimal reproductive benefit but significant social function.
While both sources agree on the ancient origins and broad occurrence of kissing, the NYT highlights the behavior's symbolic and emotional significance, whereas The Independent focuses more on its evolutionary puzzle and saliva transfer evidence. The divergence lies in the emphasis: one on behavioral diversity, the other on evolutionary history.
How we got here
Scientists have long debated the evolutionary purpose of kissing, a behavior prevalent in humans and some animals. Recent studies reconstruct the history of kissing through primate family trees, revealing its origins in prehistoric large apes around 21 million years ago. The behavior persists across species, including Neanderthals, suggesting deep evolutionary roots.
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The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the world's second-oldest university in continuous operation