Danaus eresimus, commonly known as the Soldier Butterfly, is a medium-sized butterfly in the family Nymphalidae, closely related to monarchs and queens. It is recognized by its rich orange wings bordered with dark brown to black, accented with small white spots along the margins. Compared to the Monarch (Danaus plexippus), the Soldier is typically darker and more uniform in color, with fewer bold black veins and a deeper, reddish-orange tone. The underside is similar but slightly paler, allowing some camouflage when at rest. Like other members of the genus Danaus, the caterpillars feed on plants in the milkweed family (Apocynaceae), including species such as Asclepias. By consuming these toxic plants, the larvae—and later the adults—become chemically protected from predators, advertising their unpalatability with their bright coloration.