The effects of litter size on nest building and retrieving in mice

The present study investigated the changes in maternal responsiveness (as measured by two response variables, nest building and retrieving) in three experimental litter-size conditions of three, five, and seven pups per litter, over a period of 21 days following parturition. The purpose of this study was to trace the decline of the maternal responsiveness in normal maternal mice with different litter sizes. Data obtained demonstrated that mothers given small litters (3 pups) behave significantly more maternally toward their pups than those given large (7 pups) or medium-size litters (5 pups). All females displayed a high frequency of nesting behavior immediately before and following parturition. The present investigation supports the hypothesis that experiences of the mother with her litter influences the amount and quality of her maternal responsiveness.