The red-tailed green rat snake is a thin-bodied, semi- arboreal species, which has an average adult length of 60 to 70 inches. There is not a notable sexual dimorphism in relation to size or color. Naturally endemic to Southeast Asia, red-tailed green rats range throughout Burma, Laos, Thailand, Vietnam, Cambodia, Indonesia, Singapore and Malaysia, and the Philippines. This species is at home in warm, humid forest growth rich in bamboo, where its strong tail and muscular structure function perfectly.
They feed mostly on birds, and their eggs and nestlings. They also eat frogs, lizards and small mammals. They are non-venomous snakes. They kill their prey by constriction, squeezing tightly to suffocate the prey. In their tropical environments these snakes breed year-round. Females can produce three to four clutches in one year. Clutch size is five to twelve eggs and eggs hatch in 65 to 70 days. Adult length varies with location. Snakes from the mainland seem to get bigger than those from island populations.
Their color is an example of countershading; the green on the back blends in with the lush foliage while the yellowish green on the underside matches the leaf-filtered light. Evolutionarily they have evolved to look and behave like a venomous pit viper which occupies the same habitat (mimicry). In cross-section the snake has a triangular shape with the broader belly providing increased surface contact as it climbs through branches.