Introduction

Cercopithecid monkey life histories include a period between weaning and sexual maturation when juveniles of both sexes continue to reside with their mothers. In many species, especially among the Cercopithecinae, mature daughters live in their natal group throughout their life span. This social system allows maternal influence on the behavior, development, and reproduction of offspring to extend far beyond early infancy. In such societies, mothers have the opportunity to influence their lifetime reproductive success, not only through production and care of infants, but also through maternal care that promotes survival of juvenile offspring and the reproduction of adult daughters.

Field studies of the 1960s produced detailed descriptions of mother-infant behavior (DeVore, 1963; Jay, 1963; Struhsaker, 1971; Ransom and Rowell, 1972), but the more subtle relationships between mothers and their older offspring were more difficult to detect, and kinship among older animals was rarely known with certainty. Since that time, longitudinal studies of individually recognized animals in captive and freeranging populations have documented the ongoing nature of the mother–offspring and, particularly, the mother–daughter relationship. Longitudinal data on known individuals are now available for numerous free-ranging populations of macaques (Macaca), baboons (Papio), vervet monkeys (Chlorocebus aethiops, s.l.), and Hanuman langurs (Semnopithecus entellus) (e.g. Koyama, 1970; Kurland, 1977; Hasegawa and Hiraiwa, 1980; Horrocks and Hunte, 1983; Altmann et al., 1988; Cheney et al., 1988; Dittus, 1988; Rhine et al., 1988; Mori et al., 1989; Nakamichi, 1989; Smuts and Nicolson, 1989; Borries et al., 1994).