Study One conditioning results. A. LD prairie mate pairs demonstrated a significant increase in proportion of time spent on CS+ bedding (p = 0.0049, paired t-tests). B. Individual data for prairie vole mate pairs showing male and female conditioning (2-way ANOVA: effect of conditioning: p > 0.0073; no effect of sex: p = 0.1920). C. No significant differences were observed between peer groups or prairie vole groups, but prairie vole mate pairs spent significantly more time on the CS+ bedding than meadow vole peer groups (one-way ANOVA). Letters denote groups that are significantly different with post-hoc Tukey’s HSD. * p < 0.05, ** p < 0.01, *** p < 0.005, NS = not significant.