Ecological constraints on the development of infant independence in rhesus.

Abstract

Mother-infant dyads were observed among three populations of rhesus monkeys (Macaca mulatta) in India and Nepal. This research had three purposes: 1) to examine the influences of maternal activities (ie, feeding, locomotion, and rest) and arboreality on the early development of infant independence; 2) to determine whether interpopulation differences in the development of infant independence can be accounted for by correlated differences in maternal time budgets and the amount of time infants spent on the ground; and 3) to explore how patterns of maternal care may or may not mitigate increased risk of infant mortality resulting from human harassment. Despite significant interpopulation differences in maternal time budgets, the amount of time infants spent on the ground, and the degree of harassment the animals experienced, few interpopulation differences in infant development could be found. The application of a multiple regression/ correlation analysis revealed that the development of infant independence was affected by the above factors but that those factors were acting in complementary ways to constrain development and to minimize the differences across populations.