{"id":312357,"date":"2025-11-22T23:47:20","date_gmt":"2025-11-22T23:47:20","guid":{"rendered":"https:\/\/peraltafinancing.com\/aerospace\/how-did-humans-end-up-smooching-on-the-lips-it-may-have-started-out-with-a-21-million-year-old-kiss\/"},"modified":"2025-11-22T23:47:20","modified_gmt":"2025-11-22T23:47:20","slug":"how-did-humans-end-up-smooching-on-the-lips-it-may-have-started-out-with-a-21-million-year-old-kiss","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=312357","title":{"rendered":"How Did Humans End Up Smooching on the Lips? It May Have Started Out With a 21-Million-Year-Old Kiss"},"content":{"rendered":"


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Our ancient primate relatives\u2014including Neanderthals\u2014may have enjoyed a nice peck on the lips. But researchers still don\u2019t know why we do it<\/h2>\n
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Sara Hashemi<\/a><\/p>\n

– Daily Correspondent<\/span><\/p>\n

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Chimpanzees, like some other apes, kiss each other on the lips.\u00a0
\n John More via Getty Images<\/span>
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Kissing, for all popularity, is a bit of a mystery. Scientists have long debated when humans\u2019 ancestors first put their lips together, and whether the act is simply a cultural trait.<\/p>\n

A new study suggests giving someone a peck has a long history, dating up to around 21 million years ago, long before modern humans existed. The work was published in the journal\u00a0Evolution and Human Behavior<\/em><\/a>\u00a0<\/em>on November 19.<\/p>\n

\u201cKissing seems a bit of an evolutionary paradox,\u201d Matilda Brindle<\/a>, an evolutionary biologist at the University of Oxford and co-author of the study, says to Chris Simms at\u00a0New Scientist<\/em><\/a>. \u201cIt probably doesn\u2019t aid survival and could even be risky in terms of helping pathogen transmission.\u201d<\/p>\n

But humans aren\u2019t the only primates that like to smooch. Some monkeys and apes, including gorillas, chimpanzees and rhesus macaques, also kiss. So, Brindle and her team speculated that kissing may have been a behavior passed down from ancestors that lived long before modern humans (Homo sapiens<\/em>), which evolved around 200,000 to 300,000 years ago<\/a>.<\/p>\n

First, the researchers had to figure out what constitutes a kiss. That task proved challenging, because several mouth-to-mouth behaviors resemble kissing, according to an Oxford\u00a0statement<\/a>. They settled on defining of kissing as \u201cnon-aggressive, mouth-to-mouth contact that did not involve food transfer.\u201d<\/p>\n

Brindle and her colleagues then scoured the scientific literature\u2014and even YouTube videos\u2014to collect data on kissing behavior in modern primates. With that information, the team mapped out a family tree of primates and ran computer simulations of various evolution scenarios to estimate the probability of different ancestors kissing.<\/p>\n

The results suggested that kissing evolved in a common ancestor that lived around 21.5 to 16.9 million years ago.<\/p>\n

\u201cIt would be very unlikely that kissing independently evolved in all of these species of ape that we\u2019re very closely related to,\u201d Brindle tells the Washington Post<\/em><\/a>\u2019s Leo Sands \u00a0\u201cIt makes much more sense that this is kind of an ancient trait within our primate family tree.\u201d<\/p>\n

Neanderthals may have also smooched one another, as the researchers found an 84 percent chance that humans\u2019 extinct relative engaged in the behavior.<\/p>\n

\u201cObviously, that\u2019s just Neanderthals kissing; we don\u2019t know who they\u2019re kissing,\u201d Brindle explains to\u00a0New Scientist.<\/em>\u00a0\u201cBut together with the evidence that humans and Neanderthals had a similar oral microbiome and that most humans of non-African descent have some Neanderthal DNA, we would argue they were probably kissing each other, which definitely puts a much more romantic spin on human-Neanderthal relations.\u201d<\/p>\n

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Fun fact: When was the first record of humans kissing?<\/h4>\n

One of the oldest depictions of a romantic kiss was etched into a clay tablet in Mesopotamia<\/a> around 4,000 years ago. Translated into English, it reads: \u201cMy upper lip becomes moist, while my lower lip trembles! I shall embrace him, I shall kiss him.\u201d\u00a0<\/p>\n<\/p><\/div>\n<\/div>\n

Researchers still don\u2019t know why we kiss. Brindle offers\u00a0New Scientist<\/em>\u00a0two hypotheses. One is that it enhances reproductive success by sexually arousing animals or allowing them to assess the quality of potential mates. The second idea is that kissing evolved from grooming, and that the behavior helps strengthen social bonds.<\/p>\n

\u201cChimpanzees will literally kiss and make up after a fight,\u201d Brindle says to the outlet.<\/p>\n

William Jankowiak<\/a>, an anthropologist at the University of Nevada, Las Vegas who was not involved in the study, tells the\u00a0Washington Post<\/em>\u00a0that while it’s useful for scientists to look at kissing in other primates, the study hasn\u2019t answered an important question about the behavior.<\/p>\n

\u201cIf kissing were essential to mate evaluation or to reproductive success, why have so many [human] cultures ceased to practice it?\u201d he asks. Jankowiak co-authored a 2015\u00a0study<\/a>\u00a0that found romantic kissing is present in only 46 percent of 168 sampled human cultures.<\/p>\n

Still, the new research may open a path toward finding the answer. \u201cThe social norms and context vary widely across societies, raising the question of whether kissing is an evolved behavior or cultural invention,\u201d says\u00a0Catherine Talbot,<\/a>\u00a0a study co-author and animal cognition researcher at the Florida Institute of Technology, in the statement.<\/p>\n

\u201cThis [new study] is the first step in addressing that question.\u201d<\/p>\n

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