Density Triggers Maternal Hormones That Increase Adaptive Offspring Growth in a Wild Mammal

Abstract

Thank Your Mother Maternal effects and influence can sometimes prepare unborn offspring for some of the environmental conditions they may face. Dantzer et al. (p. 1215 , published online 18 April) monitored a population of red squirrels and found that both natural and artificially induced increases in the number of conspecific calls increased the growth rate of pups because of increased glucocorticoid levels in the mother. The density stress experienced by mothers thus appears to stimulate them to produce pups that will grow faster and hopefully outcompete the many other pups expected to be produced in the dense population.