"in the higher mammals, the inborn physiologic controls of sexual behaviour are not sufficient to guarantee 'successful' mating, but have to be augmented by learning."
Since the controlled experiments of the zoologists Harry and Margaret Harlow at the University of Wisconsin (See "Social Deprivation in Monkeys", Sci.Amer. 207 1962, 136-146) it is now generally recognised that monkeys and apes need sexual training in their childhood; without it they evolve into sexual invalids. If the young male monkey is not embraced, caressed, carried and fondled by its mother, it grows to be a bad-humoured bachelor and does't mate at all. Without frequent body-contact with others (mutual grooming, for example) the young monkey will be abnormal, emotionally troubled and asocial (Alcock 1976,p.116-117). If he cannot have varied sex-play with other young monkeys, he won't be able to perform intercourse when he reaches adulthood (Bornemann 1978,p.514; Gagnon 1965,p.216; Kruijt 1976,p.35,37; West 1977,p.118)
Rhesus monkeys, for example, copulate with the female standing with her hands and feet planted firmly on the ground while the male mounts her from behind, putting his hands upon her haunches and clasping her calves with his feet. The animals learn this behaviour in the first year of their lives, by imitation, and if they are given no opportunity to do this they are quite unable to perform it later
In one experiment, a male and a female chimpanzee, each raised in isolation, were brought together as adults. Both masturbated regularly, but they never touched each other.