The influence of repeated motherhood on periparturitional behavior in cynomolgus macaques (Macaca fascicularis)

Abstract

We studied the influence of parity on periparturitional behavior by quantitatively comparing the behavior of 10 primiparous and 11 multiparous cynomolgus macaques. We found a considerable number of significant differences, some of them affirming the outcome of previous descriptive studies. During the prepartus phase, primiparae showed more locomotion and “action postures” and fewer “resting postures” than multiparae. Further, primiparae spent more time straining than multiparae and were straining in a greater variety of postures than multiparae, which were straining predominantly in a squatting posture. In the postpartus phase, primiparae needed more time than multiparae to get their young in ventroventral position. Primiparae licked mainly the newborn;multiparae licked mainly their own bodies. Finally, fewer primiparae than multiparae ate the placenta. The discussion extensively treats theories concerning parity effects. We explain behavioral differences between primiparae and multiparae in terms of novelty of the female’s internal state and novelty of the neonate and in terms of learning. We stress that the mechanism behind the so-called parity effect cannot be revealed without paying more attention, next to learning, to age, to experience with pregnancy, and to experience with parturition. Further, we argue that the immediate acceptance of the newborn at birth and the differences between primiparae and multiparae might play a crucial role in the search for the mechanism behind the onset of maternal behavior.