Boa Constrictor, a large American snake related to the anaconda. Boa constrictors reach a maximum length of more than 18 feet (5.5 m), although most are less than 15 feet (4.6 m) long. They climb trees readily. The snake inhabits Central and South American lowlands from the coasts of Mexico to central Argentina. It bears its young alive. Boas have a pair of vestigial hind limbs in the form of short, movable spurs.

Boa constrictorsBoa constrictors squeeze their prey to death.

The boa is not poisonous. It feeds on monkeys, young peccaries and tapirs, agoutis, and birds. The snake seizes its prey with great speed and, holding on with its teeth, coils its body around the prey. As the prey exhales, the snake tightens its coils to cut off breathing and probably also heart action. Finally the snake uncoils and then swallows its food whole. It is aided in swallowing by a large flow of saliva and by jawbones that can be stretched widely apart. In the inactive condition that follows, the boa is sometimes helpless before attackers. Although a boa could kill an adult human, it could not swallow anything so large.

The boa constrictor is Constrictor constrictor of the boa family, Boidae.