IS THE REDUCTION OF BIRTH INTERVALS AN EFFICIENT REPRODUCTIVE STRATEGY IN TRADITIONAL MOROCCO

Birth interval lengths are analysed from reproductive life histories o f 517 Berber peasant women of the region of Marrakesh (Southern Morocc o), whose fertility developed in a full traditional context. The high mortality rates associated with short birth intervals indicate that a rapid succession of births is detrimental to the progeny. The reproduc tive efficiency of the traditional propensity to a large family size i s therefore examined by means of two different evaluations of reproduc tive success: the 'absolute' reproductive success (the absolute number of offspring surviving to maturity) and the 'relative' reproductive s uccess (the proportion of live born surviving to maturity). The first shows that close pregnancies increase the fertility rate to such an ex tent that the associate higher number of deaths is more than compensat ed for, so that the women practising short birth intervals produce mor e surviving offspring than the others by the end of their reproductive life. The second shows that the probability of survival is directly a ssociated with birth interval length, the efficiency of the reproducti ve process being therefore greater as birth intervals grow. It is sugg ested that these two behaviours are not contradictory, and that they r epresent two successive steps of the same reproductive adjustment to e volving environmental conditions.