South American Bushmaster

Adults grow to an average of 2 to 2.5 m (6½-8 feet), although 3 m (10 feet) is not too unusual. The largest recorded specimen was 3.65 m (12 feet) long, making the species the longest of all vipers and the longest venomous snake in the Western Hemisphere. Lachesis muta is the third longest venomous snake in the world, exceeded in length only by the king cobra and the black mamba. Weight in this species is estimated at an average of 3 to 5 kg (6.6 to 11.0 lb), somewhat less than the heaviest rattlesnakes (like the eastern diamondback rattlesnake) or Bitis vipers (such as the Gaboon viper and rhinoceros viper). The head is broad and distinct from the narrow neck. The snout is broadly rounded. There is no canthus. A pair of small internasals is present, separated by small scales. The supraoculars are narrow. Other parts of the crown are covered with very small scales. Laterally, the second supralabial forms the anterior border of the loreal pit, while the third is very large. The eye is separated from the supralabials by 4-5 rows of small scales. The body is cylindrical, tapered and moderately stout. Midbody there are 31-37 nonoblique rows of dorsal scales which are heavily keeled with bulbous tubercles and feebly imbricate. There are 200-230 ventral scales. The tail is short with 32-50 mainly paired subcaudals, followed by 13-17 rows of small spines and a terminal spine. …

L. muta is found in South America in the equatorial forests east of the Andes, and the island of Trinidad. The type locality is "Surinami" (Suriname). It occurs in primary and secondary forests; adjacent fields and cleared areas. In Trinidad it tends to prefer hilly and mountainous regions.

Bushmasters prey primarily on rats and mice. Birds and reptiles may occasionally be eaten. Spiny rats are favored prey items in Costa Rica. Rice rats and agoutis are other favored prey. Other prey items include porcupines, squirrels, opossums, squirrel monkeys, and frogs.

Lachesis is one of the three Fates in Greek mythology and was supposed to assign to man his term of life—something this species is certainly capable of doing. The species is similar in appearance to rattlesnakes and vibrates its tail vigorously when alarmed, but has no rattle and was therefore called mutus (later muta), which is Latin for "dumb" or "mute". However, when in the undergrowth, the tail actually makes quite a loud rustling noise.

Common names. Known as the mapepire zanana or mapepire grande (pronounced ma-pa(y)-PEE za-Na-na or ma-pa(Y)-PEE GRAN-dey) in Trinidad, surucucú in the Amazon Basin (surucucu in a large part of Brazil), shushúpe in Peru, and pucarara in Bolivia. In Venezuela the species is known as cuaima or cuaima piña. In Colombia it is known as verrugosa or verrugoso due to the warty look of its scales, and in Suriname as makasneki and makkaslang. It is called ĩtsãi in the Kwaza language of Rondônia, Brazil. In the Shawi language of Peru, it is called na'shi.