Variation in Maternal Responsiveness in Free-Ranging Vervet Monkeys: A Response to Infant Mortality Risk?

A playback experiment was designed to examine whether maternal responsiveness (i.e., an aspect of parental care) to the threat of predation varies as a function of infant mortality risk in free-ranging vervet monkeys. Results show that mothers responded most intensely to the threat of predation before two periods when infant mortality risk was highest. In contrast, control females, who did not have infants during the test periods, showed no difference in responsiveness to the threat of predation. Vervet mothers appear to increase their parental care before periods of high infant mortality in order to increase their offspring's chances of survival.