Abstract: The physiological and behavioral differences between Myotis lucifugus and Pteropus vampyrus should be attributed to molecular mechanisms and deserve intensive investigation. We conducted genome-wide scan for coding sequences from the orthologue genes of seven mammalian species. Selection analyses were carried out by setting the branches leading to Myotis lucifugus and Pteropus vampyrus as foreground branches, respectively. Enrichment analyses were conducted for positively selected genes. Our results indicated that more genes exhibited positive selection in Myotis lucifugus than that in Pteropus vampyrus. The positively selected genes of the two species were enriched in different functions. The differences between Myotis lucifugus and Pteropus vampyrus represented their differentiation in biological functions, especially the functions of immunity, motor ability, energetic metabolism and sensory organ development.