We examine the relation between maternal care and the development of stress responses using a rather simple model of naturally occurring variations in maternal behavior over the first 8 days after birth.65 We characterize individual differences in maternal behavior through direct observation of mother-pup interactions in normally reared animals. These observations reveal considerable variation in maternal LG of pups (Figure 1). LG includes both body as well as anogenital licking.66 We then simply define mothers according to the frequency of pup LG, ie, high- or low-LG mothers. For the sake of most of the studies described here, high- and low-LG mothers are females whose scores on pup LG are ±1 SD above (high) or below (low) the mean for their cohort. Importantly, high- and low-LG mothers do not differ in the amount of contact time with pups; differences in the frequency of LG do not occur simply as a function of time in contact with pups. High- and low-LG mothers raise a comparable number of pups to weaning, and there are no differences in the weaning weights of the pups,
