A. Individual variation in alloparental behavior in juvenile male (M) and female (F) prairie voles. Each point represents a single non-attacking individual. The dashed line represents the lower quartile for the combined male and female controls (103 sec), which was used to identify individuals with high (≥ 103 sec, light grey) and low (< 103 sec, dark grey) levels of alloparental behavior (refer to Figure 1 legend for numbers of non-attacking individuals). B. PPT reduced the percentage of high alloparental males (* p< 0.05) and low alloparental females (**, p< 0.05) compared to their respective controls, and increased the proportion of attackers in both sexes (***, p < 0.05). #, p< 0.05 compared to the other sex within a given treatment and category. Controls (n= 44 males, 44 females), E2= 17β-estradiol (ERα and ERβ agonist, 5μg, n= 18 males, 22 females), PPT= 4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (ERα agonist, 5μg, n= 22 males, 23 females) and DPN= diarylpropionitrile (ERβ agonist, 5μg, n= 20 males, 16 females).