Anaconda

Anacondas are three species of aquatic boa inhabiting the swamps and rivers of the dense forests of tropical South America.

Two species are well-known:

The Green Anaconda (Eunectes murinus), which has been reported at up to 10 metres in length (although most individuals are considerably smaller) and, while shorter than the longest recorded species, the Reticulated Python, it is considerably heavier and is as a result the largest (i.e. heaviest) snake species currently in existence.
The Yellow Anaconda (Eunectes notaeus), which reaches a relatively smaller maximum length of 3 metres.

The Eunectes murinus (formerly called Boa murina) differs from Boa by the snout being covered with shields instead of small scales, the inner of the three nasal shields being in contact with that of the other side. The general colour is dark olive-brown, with large oval black spots arranged in two alternating rows along the back, and with smaller white-eyed spots along the sides. The belly is whitish, spotted with black. The anaconda combines an arboreal with an aquatic life, and feeds chiefly upon birds and mammals, mostly during the night. It lies submerged in the water, with only a small part of its head above the surface, waiting for any suitable prey, or it establishes itself upon the branches of a tree which overhangs the water or the track of game.

Like almost all boas, anacondas give birth to live young.

Anacondas have a reputation for bad temperament; that plus the massive size of the green species mean that anacondas are comparatively less popular as pets than other boas.