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Sealed with a kiss, millions of years before you could kiss and tell 

British scientists say they’ve traced the age of the kiss, to anywhere from 16 million to 21 million years ago, and have found that it was far more common among other species than previously understood

The kiss may date back millions of years but show business took long to shrug off its squeamishness about intimacy. In his 1946 masterpiece Notorious, Alfred Hitchcock got around the censors, which severely restricted “scenes of passion”, by breaking one long kiss between Cary Grant and Ingrid Bergman into a string of short ones interrupted with conversation. They talk over dinner plans, they touch faces and ears, then stay glued to one another as they cross the room to answer the telephone. They never kiss for more than a few seconds, but Hitchcock managed a three-minute scene that was as much sensual as restrained. Getty Images

Ali Watkins
Published 21.11.25, 06:28 AM

The act has been called many things: Centrifugal motion. Perpetual bliss. The thrill of the moment. Unstoppable. In technical terms, it is “non-agonistic interaction involving directed, intraspecific, oral-oral contact with some movement of the lips/ mouthparts and no food transfer”.

Or, as her majesty Faith Hill might say, “This kiss.” And, it turns out, it’s also really old.

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British scientists say they’ve traced the age of the kiss, to anywhere from 16 million to 21 million years ago, and have found that it was far more common among other species than previously understood.

Ants? They smooch. Fish? Kissers. Neanderthals? Yep, they puckered up, too — sometimes even with us.

But kissing, the researchers said, has always been something of a so-called evolutionary mystery. It doesn’t present much benefit for survival, it has minimal reproductive benefits, and it’s mostly symbolic.

“Kissing is a really interesting behaviour,” said Matilda Brindle, an evolutionary biologist at Oxford University who led the study. Dozens of societies and cultures use it, it’s common, and it has weighted symbolism. But, she said, “we’ve not really tested it from an evolutionary perspective”.

In prehistoric kissing, it seems, could be the primitive origins of our search for intimate connection. The act inherently requires vulnerability, and trust. It’s not always sexual and is often used among and between genders simply to show affection, and often between parents and offspring.

Though researchers found evidence of kissing in several species, they narrowed the
focus of the study mostly to
the behaviour of large apes, like gorillas, orangutans and baboons.

But the vast use of the practice surprised Brindle. She said she had expected examples of kissing among apes and humans, but was surprised to see the gentle behaviour shared between bugs, albatrosses and polar bears.

“For some reason, I didn’t expect this many of them to kiss,” Brindle said.

Among their research groups were Neanderthals, which, despite their differences, shared microbes with modern humans. It leaves open the chance,
the study said, that the two swapped spit in not-so-distant history.

Brindle said she hopes the study can be a foundation for further studies on kissing,
and determine — as the study itself notes — whether it is
more than Ingrid Bergman’s
preferred pastime. Other scientists, she hopes, might start recording their observations of these behaviours while in the field.

“If we had more data on this,” she said, “then we could really start to kind of unpack the potential kind of adaptive advantages of kissing.”

New York Times News Service

Kissing Couple Intimacy
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