Further Observations On Suckling Behaviour in Kittens, Together With Some General Considerations of the Interrelations of Innate and Acquired Responses

Abstract

AbstractThe feeding behaviour of kittens includes an appetitive searching component and a sucking response to a teat once this is found. The searching pattern is shown immediately after birth but the kittens usually do not feed until 1 or 2 hours later. This may be either because the sucking response has not yet matured or because the teats do not provide the correct releaser until milk secretion is well established. As the kittens become older the searching pattern undergoes modification which has the characteristics of trial-and-error learning. The sucking response, after a few days, becomes restricted to one teat but later as the kittens begin to become independent of the mother there is some relaxation in this restriction and teat constancy declines. The birth of two litters within 24 hours of each other allowed tests to be made of the response of the kittens to a foreign mother. At first there is no response to a foster mother's teats, including the one corresponding in position to the kitten's "own" teat. At about the same age as the kitten's teat constancy on its own mother starts to decline it begins to accept a teat on the foster mother. This indicates that the kitten's recognition of its own teat depends on a chemical factor, not on anatomical position. The adaptive significance of this behaviour is discussed. It is suggested that the reason for the difference between endogenous patterns and those synthesised in relation to individual experience is to be sought in the adaptive significance of the end results. Where selection favours a species-specific pattern an endogenous ontogeny necessarily follows. In the course of evolution the basis of certain types of behaviour has shifted from endogenous to experience-synthesised or vice versa. This implies that the differences between the two may not be very fundamental and it is suggested that any attempt to "compartmentalise" the study of behaviour is likely to be unprofitable. It may be heuristically more valuable at the present time to turn our attention to the similarities, rather than the differences, between endogenous and experience-synthesised patterns.