November 19, 2025
3 min learn
Kissing Might Have Advanced 21.5 Million Years In the past
People and their ancestors have doubtless been kissing for a really very long time
Picture by Stefano Bianchetti/Getty Photos; Illustration by Scientific American
For people, kissing holds main cultural cachet, accompanying confessions of romantic love, spiritual rituals of reverence and even betrayals, à la The Godfather Half II’s “kiss of dying.”
New analysis means that kissing most likely predates humanity and advanced between 16.9 million and 21.5 million years in the past, after the ancestor of the nice apes break up from the lesser apes, or gibbons. There’s even proof that Neandertals kissed.
“Kissing is a extremely attention-grabbing one as a result of it’s one thing people appear to take as a right,” says research lead writer Matilda Brindle, an evolutionary biologist on the College of Oxford. Surprisingly, romantic kissing has been documented in solely 46 p.c of human cultures, she says. “However for individuals who do kiss, it’s this on a regular basis act that additionally has this enormous cultural significance.”
On supporting science journalism
If you happen to’re having fun with this text, take into account supporting our award-winning journalism by subscribing. By buying a subscription you might be serving to to make sure the way forward for impactful tales in regards to the discoveries and concepts shaping our world right this moment.
Brindle and her colleagues, Catherine Talbot of the Florida Institute of Expertise and Stuart West of Oxford, needed to guage kissing from an evolutionary perspective. So that they searched by way of previous research for contemporary examples of primates smooching, outlined slightly unromantically as “non-agonistic interplay involving directed, intraspecific, oral-oral contact with some motion of the lips/mouthparts and no meals switch.” They discovered that similar to people, nice apes kiss for a wide range of causes, from conveying sexual want to indicating pleasant, affectionate emotions.
“When chimps have an argument,” she says, “they are going to typically go and actually kiss and make up afterwards.”
The researchers additionally discovered studies of kissing in all nice apes, from people to chimpanzees to orangutans, except for the jap gorilla. There have been no observations of kissing in gibbons. Based mostly on this taxonomy, the researchers estimate that kissing advanced after the nice apes break up from the lesser apes. Which means Neandertals and different human ancestors most likely kissed. Bolstering this concept, preliminary proof from DNA in historical dental plaque has proven that Neandertals and people shared oral micro organism till 112,000 years in the past, hinting that they could have kissed one another.
The primate kissing observations have been too fragmented to disclose a lot about how or why kissing advanced, nonetheless. Species that kiss are inclined to have mating techniques during which females mate with a number of males, the researchers report within the new research, which was printed within the journal Evolution and Human Conduct. Each species that kisses additionally engages in premastication, or chewing meals earlier than giving it over to a different particular person, which may very well be a precursor to kissing, Brindle says. There’s a lack of knowledge about premastication in species that don’t kiss, nonetheless, making the hyperlink tenuous.
It’s additionally unclear whether or not each platonic and sexual kissing have the identical roots, says Zanna Clay, a comparative psychologist at Durham College in England, who researches primate habits however was not concerned within the research. Kissing throughout mating is much less typically noticed within the wild than affectionate kissing, Clay says: “This research is working with a comparatively restricted dataset.”
Primate researchers haven’t centered a lot on primate kissing, Brindle concurs, saying the paper is a “cry” for researchers to gather extra knowledge. “It’s actually thrilling that we’ve traced the evolutionary historical past of kissing again to 21.5 million years in the past,” she says, “however we may achieve this way more if we had extra knowledge.”
It’s Time to Stand Up for Science
If you happen to loved this text, I’d wish to ask in your assist. Scientific American has served as an advocate for science and trade for 180 years, and proper now stands out as the most crucial second in that two-century historical past.
I’ve been a Scientific American subscriber since I used to be 12 years outdated, and it helped form the best way I take a look at the world. SciAm at all times educates and delights me, and conjures up a way of awe for our huge, lovely universe. I hope it does that for you, too.
If you happen to subscribe to Scientific American, you assist be certain that our protection is centered on significant analysis and discovery; that we’ve the assets to report on the selections that threaten labs throughout the U.S.; and that we assist each budding and dealing scientists at a time when the worth of science itself too typically goes unrecognized.
In return, you get important information, charming podcasts, good infographics, can’t-miss newsletters, must-watch movies, difficult video games, and the science world’s finest writing and reporting. You may even present somebody a subscription.
There has by no means been a extra vital time for us to face up and present why science issues. I hope you’ll assist us in that mission.
