Anaconda (snake), common name for large South American snakes that kill by squeezing prey. Anacondas are among the largest and most powerful snakes in the world. Female anacondas grow bigger than males and can reach enormous size, ranking as the heaviest of all snakes. Anacondas spend much of their time in water. They hunt reptiles and mammals, as well as fish and birds. The biggest anacondas can swallow prey as large as caimans or deer. They rarely attack humans.
The name anaconda is said to come from a Tamil word meaning “elephant killer,” originally used for pythons in Sri Lanka. Local names for the snakes in South America include the Spanish term matatoro, meaning “bull killer,” and the Native American terms sucuri, yakumama, and jibóia. Anacondas are members of the boa family and are sometimes called water boas.