Eunectes murinus
green anaconda

Green anacondas are found throughout tropical South America, east of the Andes, mainly in the Amazon and Orinoco basins and in the Guianas (Pope 1969).

These snakes are mainly aquatic, but will also hunt on land. They prefer sluggish or still waters rather than clear, swift flowing streams. As a result, they are found at relatively low altitudes. The anaconda can often be found in the shallow caves beneath the undercut banks. It usually spends its time lying in shallow waters or basking in the sun on a nearby tree branch (Pope 1969).

Eunectes murinus is dark green in color (hence the name Green Anaconda) with alternating oval black spots. Similar spots with yellow-ochre centers are along the sides of its body. The Green Anaconda has a large narrow head that is not distinct from the thick neck area. Its eyes and nostrils are set on the top of its head, which enables it to see and breathe while mostly submerged. Its body is exceptionally stocky compared to other boas and extremely muscular. This species is a constrictor and not poisonous. Adults of this species can grow to over 9 meters in length. For it's length, it is much heavier than other large constrictors, and so if weight and length are both considered, Green Anacondas are the largest snakes in the world.

The snake is covered with scales all over and has spurs (small claw like appendages on either side of the cloaca. The only area without scales is the cloaca (cavity into which the intestinal and genito-urinary tracts empty). This area contains glands that emit a foul smelling toffee colored musk, which is poisonous for small organisms. It may be a way of preventing ticks and leeches from attaching themselves to the cloaca. The pattern of scales found along the black and yellow underside of the lower tail are unique to each snake and can serve as a method of identification, much like the fingerprint of a human (Coborn 1991; Encyclopedia Britannica 1995; Kemper 1996).

This species is primarily nocturnal, and spends most of its time in water. It is sometimes referred to as the "Water Boa" and is the most aquatic of the boas. Due to its large size it may seem sluggish on land, but in the water it is capable of surprising speeds both on the surface and underwater. It usually waits in the water with only its snout extending above the surface. When an animal passes by or stops to drink, the snake grabs it with its jaws and coils around it, constricting it until it suffocates or drowns. On land it may hang in trees and grabs its prey from above, coiling around it, rendering it helpless. The victim of an anaconda is seldom crushed, the snake only squeezes hard enough to prevent its victim from breathing.

There is some evidence of anacondas congregating; however, what brings them together is not known.

Since it takes a long time to digest its food, an anaconda is often very docile after a meal and usually spends its time just lying in the sun along a river bank.

(Pope, 1969; Greene, 1997)

Green anacondas are carnivorous, and will attack any vertebrate that they can catch and swallow, especially fish, amphibians, other snakes, and mammals such as capybara. Small individuals may climb trees to raid bird nests, and the largest specimens have been known to attack caimans, small deer, and peccaries. There are few records of attacks on humans, and no recorded deaths. Like all snakes, Green Anacondas swallow their prey whole and, because they can unhinge their jaws, they can swallow prey much larger than the diameter of their mouths. They usually swallow the prey head first, as this way the limbs tend to fold. The muscles contract in waves as swallowing occurs, compressing the prey with each surge forward. Green anacondas have a slow-acting digestive system; it often takes days or weeks to digest their food. After a meal, an anaconda may not eat for weeks or months

(Coborn 1991; Rivas 2000). (Rivas, 2000)

Anacondas, because of their size and strength, can be dangerous when encountered. There are rare records of anacondas attacking humans, but no deaths.

Green Anaconda's prey on many species, including some rodents and others that may be agricultural pests.

Though not a significant part of the skin trade, anacondas do contribute to a small extent, thereby generating income and providing us with commodities made from its skin.

Anacondas are a tourist attraction in zoos, bringing in money and providing people with a form of entertainment.

(Pope, 1969)

Curently all trade in anacondas is prohibited in most South American countries; however, some have annual quotas and periodically export live snakes for zoos, research and the pet trade. Few people however take anacondas as pets due to their large size and pugnacious nature.

Some skins are traded illegally; however, this is not having a significant impact on anaconda populations as they are hard to catch and their dark scaly skin does not translate well into flashy belts, shoes and purses. The large size of the Green Anaconda leaves very few natural predators. Its greatest threat is man. Incidental killing is perhaps the greatest threat to anacondas. Most people who live near these snakes are afraid of them and routinely kill them on sight. This is largely due in part to the lack of knowledge about them and because of reliance on myths and stories depicting anacondas as man-eaters. Habitat destruction is yet another cause for the decline in anaconda populations.

At present, little is known about the anaconda. The Venezuelan Wildlife Department (PROFAUNA), the Convention on International Trade in Endangered Species of Flora and Fauna (CITES) and the Wildlife Conservation Society, in a joint effort are conducting the first field study ever done on the Green Anaconda (Eunectus murinus). The main purpose of this study will enable wildlife officials to decide whether or not a conservation program based on commercial harvesting will be viable.

(Kemper 1996; Rivas 2000)

The name "anaconda" is derived from the Tamil word "anaikolra", which stands for "elephant killer".

The early Spanish settlers used to refer to the anaconda as the "matatoro" or "bull killer".

The anaconda is the largest of the nonpoisonous boas.

Anacondas seem to have varying longevity. Some are known to live close to 30 years while others usually do not survive beyond 10 years. Despite several instances in which anacondas have lived for well over 10 years, this species is reputed to have a short longevity.

There have been trails recorded in the swamp which reach a width of six feet and support the statements of local Indians and rubber pickers that the anaconda reaches lengths of well over 60 feet.

The best way to pick up an anaconda is from its tail end.

If knowledge about anacondas is not increased amongst people, especially those living in areas where the anaconda lives, people will continue to kill them. These snakes are a unique and an important part of the ecosystem.

(Kemper 1996; Pope 1969; Coborn 1991)