Scientific Classification

Common Name

green anaconda, common anaconda, water boa

Kingdom

Animalia

Phylum

Chordata

Class

Reptilia

Order

Squamata

Family

Boidae

Genus Species

Eunectes (good swimmer) murinus (mouse colored) murinus

Fast Facts

Description

Considering mass and length, the green anaconda is the largest snake in the world. (Though the reticulated python - Python reticulatus - achieves similar lengths.) Their eyes and nostrils are located on top of the anaconda's large, narrow head - enabling it to breathe while the rest of its body is submerged. The body is exceptionally stocky compared to other boas and extremely muscular. The green anaconda is typically dark green with oval black spots. Spots with yellow-ochre centers run along the sides of its body.

Size

Averages 6 m (20 ft.) in length; average diameter is 30 cm (12 in.); reportedly can grow in excess of 10 m (32.8 ft.) in length, though individuals at this length are rare and/or poorly documented; the largest credibly documented specimen was reported to be 11.4 m (37.5 ft.) in length, though this 1944 figure is not innately accepted throughout the entire zoologic community; newborn anacondas are 30-60 cm (12-24 in.) in length

Weight

Average of 148.5 kg (330 lbs.)

Diet

Anacondas feed on aquatic and amphibious animals, including mammals, fish, caiman, birds, ducks, and turtles. There have been a few reports of cannibalism involving green anaconda females preying upon anaconda males. Scientists believe it is possible that the larger breeding females eat their smaller mating partners to survive the long, seven-month fast associated with pregnancy.

Incubation

8-12 weeks

During breeding the snakes often cluster into a breeding-ball that may consist of 2-12 males coiled around a single female. They may stay like this for 2-4 weeks.

Clutch Size: Anacondas give birth to several dozen live young at one time; young are 30-60 cm (12-24 in) in length

Sexual Maturity

Male: Approximately 18 months or 1.8 m (6 ft)

Female: Approximately 3 years or 2.7 m (9 ft)

Life Span

Average is 10 years; may exceed 30 years

Range

Found throughout tropical South America, east of the Andes, mainly in the Amazon and Orinoco basins and in Guiana

Habitat

Typically found in swamps and sluggish streams

Population

Global: No data

Status 

IUCN: Not listed
CITES: Appendix II
USFWS: Not listed

Fun Facts

1. The name "anaconda" is derived from the Tamil word "anaikolra", which means "elephant killer." Early Spanish settlers referred to the anaconda as "matatoro" or "bull killer."
2. Though anacondas are excellent swimmers, they will also hang from branches to dry off.
3. The only area on the anaconda's body without scales is the cloaca. Glands in this area emit a foul smelling musk, which is poisonous for small organisms. Scientists believe the musk may prevent ticks and leeches from attaching themselves to the cloaca.

Ecology and Conservation

Currently, trade in anacondas is prohibited in most South American countries; however, some are periodically exported for zoos, research, or pet trade. Few people however take anacondas as pets due to their large size and potential aggressive nature.

Anaconda skins are traded illegally, but the practice does not seem to have a significant impact on species populations. One possible reason is that they are hard to catch and their dark skin does not typically make a flashy belt, shoes, or purse.

Green Anacondas have very few natural predators because of their large size. Their greatest threat is man due to lack of knowledge about them and because of myths and stories depicting anacondas as man-eaters. Habitat destruction is another cause for the decline in anaconda populations.

Bibliography

Bauchot, Roland (ed.). Snakes a Natural History. New York: Sterling Publishing Co., Inc., 1994.

Ernst, Carl H., and Zug, George R. Snakes in Question. Washington: Smithsonian Institution Press, 1996.

Mattison, Chris. Snakes of the World. New York: Facts on File Publications, Inc., 1986.

Mehrtens, John M. Living Snakes of the World. New York: Sterling Publishing Co., Inc., 1987.

Rivas, J. A. and R. Y Owens. Eunectes murinus (Green anaconda): cannibalism. Herpetological Review. 31. 2000.