Kissing is not universal among human beings, and, even today, there are some cultures that have no place for it. This suggests that it is not innate or intuitive, as it so often seems to us. Another possibility is that kissing is a learned behavior that evolved from "kiss feeding," the process by which mothers in some cultures feed their babies by passing masticated food from mouth-to-mouth. Yet, there are some modern indigenous cultures in which kiss feeding is practiced, but not social kissing. Kissing could also be a culturally determined form of grooming behavior, or, at least in the case of deep or erotic kissing, a representation, substitute for, and complement to, penetrative intercourse.
Whatever the case, kissing behavior is not unique to human beings. Primates such as Bonobo apes frequently kiss one another; dogs and cats lick and nuzzle one another, and members of other species; even snails and insects engage in antennal play. It could be that, rather than kissing, these animals are in fact grooming, smelling, or communicating with one another, but even so, their behavior implies and strengthens trust and bonding.
Vedic texts from ancient India seem to talk about kissing, and the Kama Sutra, which probably dates back to the 2nd century, devotes an entire chapter to modes of kissing. Some anthropologists have suggested that the Greeks learned about erotic kissing from the Indians when Alexander the Great invaded India in 326 BC. However, this need not mean that kissing originated in India, or indeed that it does not predate the oral roots of the Vedic texts. In Homer, which dates to the 9th century BC, King Priam memorably kisses Achilles’ hand to plead for the return of his son’s cadaver:
Respect the gods, Achilles, and show mercy towards me, remembering your own father, for I am more to be pitied than he, since I have brought myself to do what no other man on earth would do, I have lifted to my lips the hand of the man who killed my sons.
In his Histories, which date to the 5th century BC, Herodotus speaks of kissing among the Persians, who greeted men of equal rank with a kiss on the mouth and those of slightly lower rank with a kiss on the cheek. He also reports that, because Greeks ate of the cow, which was sacred to the Egyptians, the Egyptians refused to kiss them on the mouth. Kisses also feature in the Old Testament. Disguised as Esau, Jacob kisses the blind Isaac and thereby steals his brother's blessing. In the Song of Songs, which celebrates sexual love, one of the lovers implores, "Let him kiss me with the kisses of his mouth, for thy love is better than wine."
Under the Romans, kissing became more widespread. The Romans kissed their partners or lovers, family and friends, and rulers. They distinguished a kiss on the hand or cheek (osculum) from a kiss on the lips (basium) and a deep or passionate kiss (savolium). Roman poets such as Ovid and Catullus celebrated kissing, as, for example, in Catallus 8:
Goodbye girl, now Catullus is firm, he doesn’t search for you, won’t ask unwillingly. But you’ll grieve, when nobody asks. Woe to you, wicked girl, what life’s left for you? Who’ll submit to you now? Who’ll see your beauty? Who now will you love? Whose will they say you’ll be? Who will you kiss? Whose lips will you bite? But you, Catullus, be resolved to be firm.
Roman kisses fulfilled purposes from the social and political to the sexual. In an age of widespread illiteracy, kisses served to seal agreements; thus the expression "to seal with a kiss" and the "X" on the dotted line. The social status of a Roman citizen determined the part of the body on which he or she could kiss the emperor, from cheek to foot. Couples got married by kissing in front of a gathered assembly, a practice that has been carried into this day.
Practices changed with the decline of Rome and the rise of Christianity. Early Christians often greeted one another with a "holy kiss," which was believed to be associated with a transfer of spirit. The Latin anima means both "breath of air" and "soul," and, like animus (mind), derives from the Proto-Indo-European root ane- (to breathe, blow). Although St. Peter had spoken of the "kiss of charity," and St Paul of the "holy kiss," early church sects omitted kissing on Maundy Thursday, the day of the year on which Judas betrayed Jesus with a kiss. Outside the Church, kissing was used to cement rank and social order—for example, subjects and vassals kissed the robe of the king or the ring or slippers of the pope.
After the fall of Rome, the romantic kiss seems to have disappeared for over 1,000 years, to re-emerge at the end of the 11th century with courtly love. The kiss of Romeo and Juliet is emblematic of this movement, which sought to remove courtship from the control of family and society and celebrate romantic love as a liberating, self-determining, and potentially subversive force. The fate of the star-crossed lovers reminds us that such careless freedom is not without risks, and it could be that vampirism evolved as a representation of the dangers—to health, rank, reputation, prospects, and happiness—of kissing the wrong person.