[Study of suckling behavior in the rat: the effects of food deprivation of pups and lactational age of mother].

The effects of food deprivation (0-1, 2-3, and 22-23 h) of pups and of lactational age of mother (1-7 days, 16-22 days and own mother) upon suckling behavior of pups were investigated with the mother anesthetized. The effect of food deprivation was not evident prior to 11 days of age but deprived pups showed higher level of suckling than non-deprived pups at 16 and 21 days of age (Experiment 1). The effect of lactational age of mother was not found at 6-17 days of age but pups at 1-2 and 21-22 days of age showed lower level of suckling to the anesthetized mother which differed in lactational age from their own mother (Experiment 2).