The first kiss in history probably took place over 16.9 million years ago — long before humans even existed, a new study suggests.
Despite its popularity in many cultures among lovers, family members and friends, kissing has long perplexed evolutionary biologists, given it has no obvious benefit to either reproducing or finding food, while carrying the risk of disease transmission. A 2015 study even found that fewer than half of cultures actually practiced romantic-sexual kissing — leading some to speculate that kissing could be a purely cultural trait.
