1979 年 50 巻 2 号 p. 73-81
The mother-infant interaction was studied in the mouse by changing the size of litters. Litter size was reduced to either two or eight on the day following parturition, and the behavior of the mothers was observed by the time-sampling technique during the entire lactation period. There was no significant difference in their maternal behavior, (nursing, licking pups, and nest bulding). The mothers of the small litters were less active and spent more time resting than the mothers of the large litters. The offspring were re-grouped at weaning (21 days of age) into groups of two or eight of the same sex, and tested in an open field at nine weeks of age. The pre-weaning litter size and the post-weaning group size affected different aspects of the open-fieldbehavior.