South America


Rain forests and wetlands

Heavy-duty snake

The name anaconda actually refers to the Eunectes genus, but it is most often used to refer to one species, the green or common anaconda. A member of the boa family, Boidae, South America’s green anaconda is the heaviest snake in the world, having the greatest girth in proportion to its length of any snake.

The green anaconda is normally some shade of brownish-green, olive, or grayish-green and patterned with egg-shaped black spots. The Beni or Bolivian anaconda is similar but is found only in a small region of Bolivia. The smaller yellow or Paraguayan anaconda has a pattern of blotches, saddles, spots, and streaks (usually black or dark brown) against a yellow, golden-tan, or greenish-yellow background. The dark-spotted anaconda is about the same size as the yellow anaconda and is brown with large dark spots.

The water’s fine!

The anaconda lives over a vast area of tropical river systems and swamps in South America, east of the Andes. This hot, humid region with its dense foliage offers excellent habitat for such a large snake, which fits well into this world. The anaconda likes to be in or near water and spends a large part of its time in the murky waters that help to hide, as well as support, its tremendous body.

Anacondas are excellent swimmers and divers. Their eyes and nasal openings are on top of their head, so the snakes can wait for prey while remaining nearly hidden by the water. Anacondas rest and sun themselves along the bank of a river or in tree branches that hang over water along riverbanks so the snakes can quickly drop into the water if needed.

Female green anacondas are much larger than males.
A group of anacondas is called a bed or knot.
Despite their fearsome reputation, anacondas are not venomous.
Anacondas are also known as water boas.
The water-loving anaconda’s species name, “Eunectes,” is from a Greek word meaning good swimmer.
The anaconda’s mouth is able to open up to three times the size of its head.

The San Diego Zoo’s first anacondas arrived in 1939. Today, a pair of green anacondas can be seen in a corner exhibit of our famous Reptile House. The male was born in 1998 and the female in 2008. Look for the two lounging in their pond, draped in the branches, or coiled under a log.

Humans are the anaconda’s most dangerous predator. Green anacondas, for example, face a number of threats that could severely reduce their numbers in the wild. These huge snakes are hunted, both legally and illegally, in many parts of South America for their skin and for sale in the growing illegal pet trade. Anacondas do NOT make good pets; they can quickly outgrow their cage, are dangerously strong, and release an unpleasant odor when bothered.

Local people also frequently kill anacondas, saying they are just trying to protect their livestock, pets, and families. The sad truth is that oftentimes these snakes are killed just because people fear and dislike them.