The kiss, curiously enough, is found both in certain animal and human races but not in all human races.
Many mammals, birds and insects exchange caresses which remind one of the human kiss. "Love birds" seem to spend much of their time kissing each other.
On the other hand, Eastern races do not seem to relish the caress which Western peoples call a kiss. In China a form of affectionate greeting corresponding to our kiss consists in rubbing one's nose against the cheek of the other person after which a deep breath is taken thru the nose with the eyes half-shut.
In some primitive races the equivalent for our "kiss me" is "smell me." In other races, the kiss is a manifestation of respect rather than a proof of love. Anglo Saxons on certain occasions kiss the Bible. In the early Christian and Arab civilisations, the kiss was a ritual gesture and has remained so in certain Catholic customs: kissing the pope's foot, relics, a bishop's ring, etc.
In certain races, kissing is a proof of affection but not of love. Japanese mothers kiss their children but Japanese lovers do not exchange caresses of the lips, according to Lafcadio Hearn.
The dark races of Africa are ignorant of that caress and so are the Malays, the aborigines of Australia and many other primitive tribes.
The Birth of the Kiss. It appears that even among the kissing races, the kiss is a relatively recent development. It is rarely mentioned in Greek literature. In the Middle Ages it was a sign of refinement, being almost unknown among the lower classes.
Some analysts have come to the conclusion that the kissing habit is derived from sucking the mother's nipple.
If this was the proper explanation, all the races would naturally indulge in it.
The kiss is infinitely more complicated than that. The Freudian explanation should not be discarded entirely but it does not explain everything.