Humans do it, monkeys do it, even polar bears do it. And now researchers have reconstructed the evolutionary origins of kissing.
Their study suggests that the mouth-on-mouth kiss evolved more than 21 million years ago, and was something that the common ancestor of humans and other great apes probably indulged in.
The same research concluded that Neanderthals may have kissed too – and that humans and Neanderthals may even have smooched one another.
The scientists studied kissing because it presents something of an evolutionary puzzle – it has no obvious survival or reproductive benefits, and yet it is something that is seen not just in many human societies, but across the animal kingdom.
By finding evidence of other animals engaging in kissing, scientists were able to construct an “evolutionary family tree” to work out when it was most likely to have evolved.
To ensure that they were comparing the same behaviour across different species, the researchers had to give a very precise – rather unromantic – definition to a “kiss”.
In their study, published in the journal Evolution and Human Behaviour, they defined kissing as non aggressive, directed oral-oral contact “with some movement of lips or mouthparts and no food transfer”.
“Humans, chimps, and bonobos all kiss,” explained lead researcher Dr Matilda Brindle, an evolutionary biologist from the University of Oxford. From that, she concluded, “it’s likely that their most recent common ancestor kissed.”
“We think kissing probably evolved around 21.5 million years ago in the large apes.”
In this study, scientists found behaviour that matched their scientific definition of kissing in wolves, prairie dogs, polar bears (very sloppy – lots of tongue), and even albatrosses.
They focused on primates – and apes in particular – in order to build an evolutionary picture of the origin of the human kiss.
Credit: bbc.com
