California Deermice are nocturnal, with peak activity periods near dusk and dawn. Adults are fairly sedentary, spending much of their time nesting under fallen logs or debris, in trees, or in the dens made by other rodents. Learn more about the Peromyscus californicus, more commonly known as a California Deermouse, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.