A study by a Canadian anthropologist demonstrated that 97 percent of women shut their eyes during a kiss but only 37 percent of men did. The late actor Anthony Quinn had an explanation: “Many a husband kisses with his eyes wide open. He wants to make sure his wife is not around to catch him.”

Kissing on the lips is something the Romans started. A husband returning from work would kiss his wife’s lips to see if she’d been drinking during the day. In fact, the Romans were so keen on kissing that Emperor Tiberius was obliged to ban the practice after an epidemic of lip sores.

The French kiss itself was invented in the Brittany village of Pays de Mont as a substitute for sex because the population was growing too fast.

In writing, XXXs have been used to represent kisses. The origins of this go back to the days when people couldn’t write signed their name with an X. To emphasize their sincerity, they would then kiss their mark. This practice of kissing the X led to the X’s representing a kiss.

Human beings are not the only mammals that kiss. Polar bears and kangaroos kiss. Chimpanzees can and do French kiss. Sea lions rub mouths, a male mouse licks the mouth of a female mouse, and an elephant sometimes brushes its trunk against another elephant’s lips.

An American insurance company discovered that men were less likely to have a car accident if they were kissed before they set off.

Germans rub noses, as do a good many other peoples. Polynesians like a nose rub but also enjoy the mitakuku, which involves biting hairs from eyebrows. Trobriand islanders bit each other’s eyelashes. In China they touch each other’s cheeks and then sniff.