The lab employs a diverse array of approaches, ranging from computational models to the molecular analysis of gene expression. This work is strongly anchored in empirical studies of animal behavior in both the laboratory and field. Using "exotic" rodent models, we focus on the nature and consequences of within- and between-species variation in neuronal gene expression and behavior. For example, we study how individual differences in the neuronal distribution of vasopressin receptors contribute to social attachment, space-use and sexual fidelity in the socially monogamous prairie vole. Another major model concerns the production and perception of advertisement songs in the singing mouse -- a project that includes neuroanatomical studies, field playbacks, and population genetic analysis of song variation. These projects involve substantial field components in both the U.S. and Central America.