ABSTRACT
R. W. Wrangham argues that monogamy and subsequent high male parental investment evolved as a direct consequence of the inability of females to maintain an exclusive territory, which they need and which can only be secured by the added contribution of a permanent, adult mate. The marmoset-tamarin offsprings' learning environment prepares them for the shared parental roles they, too, will play as adults, and the degree of competence and experience gained in childhood from caring for siblings will later be translated into reproductive success. The cross-cultural data on multiple care giving within what has been called "polymatric" societies, as compared with societies in which there is a single care giving figure, so-called "monomatric" societies, indicate that there is a need to better evaluate what constitutes infant care among humans. Thus far, the two major families of Old World monkeys have been considered and have mostly focused upon one form of surrogate care giving,—namely, care extended by other females.
