ETYM Latin boa a kind of water serpent. Perh. from bos an ox.
Any of several chiefly tropical constrictors with vestigial hind limbs.
Any of various nonvenomous snakes of the family Boidae, found mainly in tropical and subtropical parts of the New World. Boas feed mainly on small mammals and birds. They catch these in their teeth or kill them by constriction (crushing the creature within their coils until it suffocates). The boa constrictor Constrictor constrictor can grow up to 5.5 m/18.5 ft long, but rarely reaches more than 4 m/12 ft. Other boas include the anaconda and the emerald tree boa Boa canina, about 2 m/6 ft long and bright green.
Some small burrowing boas live in N Africa and W Asia, while other species live on Madagascar and some Pacific islands, but the majority of boas live in South and Central America. The name boa is sometimes used loosely to include the pythons of the Old World, which also belong to the Boidae family, and which share with boas vestiges of hind limbs and constricting habits.