tropical American rear-fanged snake of the family Colubridae. The mussurana preys on both rodents, which it kills with its venom, and on other snakes, which it kills by constriction. It is largely immune to the venom of members of the genus Bothrops (fer-de-lance and allies), its chief prey. The mussurana may be 2.1 m (about 7 feet) long. Adults are blue-black or brown, with a white belly stripe; the young are pink, with dark head and collar.