Infant-related influences on birth intervals in rhesus monkeys

That a mother's relationship with her infant could influence her subsequent reproductive history can be argued as follows. A rhesus monkey infant whose next sibling is to be born in a succeeding birth season could compete with it by trying to postpone the date when its mother next conceives. If the mother preferred a shorter delay than the infant, processes of conflict and negotiation involving the two could show in some of the behavioural interactions constituting their relationship. For example, a mother could try to hasten the onset of her next pregnancy by trying to promote more independent behaviour in her infant, perhaps by rejecting some of its bids for contact. We report here studies on our rhesus monkey colony and other colonies which support this argument.