Surucucu (Lachesis muta) or Surucucu pico-de-jaca, is a venomous pit viper species found in the Amazon and Atlantic Forest. Adults grow to an average of 2 to 3 meters. The head is broad and very distinct from the narrow neck. The snout is broadly rounded. The color pattern consists of a yellowish, reddish or grey-brown ground color, overlaid with a series of dark brown or black dorsal blotches that form lateral inverted triangles of the same color.