We use genomic, morphological and environmental data to study the evolution of seasonal camouflage, a seasonal transition between summar brown color to white or gray color in winter for camouflage. Specifically, we are studying the evolution and molecular basis of seasonal coat color change in mountain hares (Lepus timidus) in Scandinavia. We conduct whole genome population genetics analysis, transcriptomic analysis, functional genetic analysis, phylogenetic analysis, and other omic analysis to understand what genes control the ability to seasonal change color and how environmental factors like light control this flexibility in phenotype.