Weaning in rats: II. Pup behavior patterns

Abstract

In this study, litters of rat pups and their mothers were continuously video‐monitored from Day 14 to Day 35 postpartum in order to describe the behavioral changes that occur during that period. Prior to the onset of solid food intake (Day 18), pups spent most of their active time suckling. During Days 18 to 26, feeding, drinking, grooming, and play‐fighting rapidly became frequent daily activities, while suckling gradually began to decline. By Day 28, pups' food and water intake relative to body weight and time allocated to the new behaviors reached asymptote. Pups nevertheless continued to suckle until Day 34. These results suggest that (1) the transition from milk to solid food is embedded in a multitude of behavioral changes; (2) these behavioral changes have distinct temporal characteristics; and (3) the developmental period between Days 14 and 34 can be divided into three phases. Apart from the fascination and the self education of watching the developing of any form of life from its early protoplasmic simplicity into that complex maturity, there is solid scientific reason that Psychology has much to hope from minute and accurate records of the developmental periods of young animals of all species (Small, 1899). Copyright © 1990 John Wiley & Sons, Inc.