AbstractThe hoarding behavior of 4 litters of Golden hamster pups (n= 3) was observed every 2nd day between the ages of 13 and 47 days (2 litters) or 13 and 55 days (2 litters). Each litter lived with the mother until Day 30; then the pups were put in social isolation. Immature forms of pouch filling and emptying, which were not integrated into coherent behavior sequences, appeared from the beginning of the observation period. Coordinated hoarding trips were shown from Day 21 onwards, once the motor patterns of inserting and extracting food had gained their definitive form. The development of hoarding was correlated with the animal's body weight and therefore with maturational factors. Mature hoarding behavior was greatly enhanced by the subject's separation from its family unit.