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.
- See more at: http://animals.sandiegozoo.org/animals/anaconda#sthash.qaPSGpe5.dpuf