The black-headed cat snake (Boiga nigriceps) gets its name from the greenish to blackish colouration of its head. Neonates and juveniles do not exhibit this dark colour on the head until adulthood. The body colour ranges from brown to orange and red to black. The ventrals are yellowish below the neck and white for the rest. They are large snakes; adults may attain a total length of 1.7 m (5 1⁄2 ft). They are quite aggressive and hardy in nature.