Kissing began as a way for humans to remove ticks and lice from each other, unromantic boffins believe.
Snogging specialists at Warwick University are convinced the practice dates back to our ancient ancestors, the apes, around seven million years ago.
They used their lips to groom one another and remove itchy critters from each other’s fur when they came down from the treetops.
There are many types of kissing but they all have in common a “protruding of the lips and slight suction”, the experts observed.
(Image: Getty Images/iStockphoto)
The practice “is performed between various individuals of a community, not just by or to babies or sexual partners”, evolutionary psychologist Adriano Lameira said.
Chimps still use their fingers to comb for pests before using their mouths at the end to nab any lingering lice and ticks.
Boffins now think the ritual has evolved to only keep the final part of the grooming session as a form of showing love.
(Image: Getty Images)
Pecking pro Mr Lameira added: “When the ape groomer closes the grooming bout by ‘kissing’ the groomed, it exhibits parallels to human kissing to an extent that no other proposed behaviour thus far has.”
The findings have been published in the journal Evolutionary Anthropology.
A 10-second kiss can transfer as many as 80 million bacteria and 700 different strains, a study published in the journal Microbiome found.
Researchers monitored the kissing behaviour of 21 couples and found that pairs who kissed at least nine times a day shared similar oral bacteria.
Oral bacteria is normal and experts believe puckering up can actually help boost your immune systems and gut health.
Nutritionist Adrienne Benjamin, of ProVen Probiotics, said: “The exchange of bacteria during kissing may introduce beneficial microbes to the oral microbiome, which can transition to the digestive system and gut microbiome.”
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