The twig or bird snakes of the genus Thelotornis are a group of back-fanged, colubrid snakes in the family Colubridae. All species have a slender and elongated profile, a long tail, narrow head and pointed snout. The eyes of each species have horizontal pupils, shaped like keyholes, which gives twig snakes binocular vision. Twig snakes are greyish-brown with faint light and dark markings. When threatened, they inflate their throat to display bold black markings between the scales.