The effect of stimuli emitted by sucklings on tactile contact of the bitches with sucklings and on number of licking acts.

Bitches changed abruptly their maternal behavior on 15th and 16th day of the maternal cycle, following an exchange - on the beginning of 15th day - of some puppies from their own litter for other 2-3 days old puppies. The total time of tactile contact with puppies on days 15 and 16 greatly increased as compared with the 13th and 14th day, i.e., the days immediately preceding the exchange of puppies. The number of licking acts also increased. In control bitches, whose puppies were not exchanged, the indices of maternal behavior showed no increase on days 15 and 16, compared with days 13 and 14 of the maternal cycle. The foster 2-3 days old puppies were also a source of much stronger stimuli releasing care-giving reactions than the own, correspondingly older puppies.