Influence of perinatal experiences on ontogeny of behaviour

Various processes occur during the perinatal period which have a crucial effect on the postnatal development ofbehaviour as well as on both the preand postnatal physiological adaptability of birds and mammals. Thus, the perinatal period is more important for life history than has commonly been supposed. This thesis is supported by investigations carfled out in birds (Muscovy ducks) and in mammals (Guinea pigs). Two issues are discussed. Firstly, normal prenatal development of physiological processes is a precondition for adaptive postnatal development. This is instanced by the prenatal development of the cardiovascular system and temperature regulation, the synchronization of hatching and the development of mother-offspring relationships in Muscovy ducks. Secondly, epigenetic adaptation mechanisms may be initiated by learning processes during the perinatal period, and may be regarded as innate even though they are not fixed in the genome. Transmission of epigenetically gained abilities may take place over more than one generation. Examples of epigenetic processes include adjustment of the thermoregulatory system, early postnatal influences on later floor preferences in Muscovy ducks and Guinea pigs, and influences on acoustic preferences in both species. Systematic investigations of behavioural processes occurring in the perinatal period may be useful in optimising the environmental conditions in which animals are kept. Social rank order of intensively kept pigs at weaning and in the early fattening phase B. Puppe, M. Tuchscherer Research Institute for the Biology of Farm Animals, Department of Basic Physiology in Animal Husbandry, 18 196-Dummerstorf, Germany