Changes in responsiveness to young in the adult mouse: The effect of external stimuli.

Abstract

Each of 200 naive female mice was presented with an infant mouse, groups of 10 being assigned to infants of ages 1 day, 2 days, and so on up to 20 days. Occurrences of retrieving, licking, nest building, and lactation position decreased with increasing age of the young. These results favor an earlier hypothesis that the mother''s waning interest in the litter from birth to weaning depends mainly upon changes in external stimuli coming from the young. The course of the decrease was not the same for the different activities; thus they did not all seem to depend upon the same external factors. Some evidence was found for a relationship of supersonic desertion calls with retrieving and nest building; licking and lactation position did not show the same dependence.