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NAS - Nonindigenous Aquatic Species |
Common Name: green anaconda
Identification:
The green anaconda is the largest snake in the world. Its solid, heavy body is olive-green to brown and patterned with numerous circular black markings scattered along its length. The scales are smooth and glossy. (Areste and Cebrian 2003, Mattison 2006 ) This particular pattern and coloration provides the snake with camouflage while it lies submerges among aquatic vegetation. These snakes also exhibit the greatest sexual size dimorphism of any terrestrial vertebrate. Breeding females are at least five times the size of breeding males (Rivas 2000).
Size: Large females can reach total lengths up to 26 ft (8m)
Native Range:
Green anacondas can be found on the Island of Trinidad and throughout northern South America. Their native range extends east of the Andes from Venezuela to Brazil and south into Bolivia and northern Paraguay (Areste and Cebrian 2003, Mattison 2006 ).
Nonindigenous Occurrences: In August 2004 a green anaconda (FLMNH 143935) was collected from Big Cypress Swamp, Collier County, Florida.
Ecology: The green anaconda is an aquatic snake usually found submerged under the water or near the water’s edge (Rivas 2000). Despite is enormous size; the green anaconda is a master of disguise. The eyes and nostrils of an anaconda are positioned high upon the head, so when the snake is completely submerged only the very top of the head is visible. The dark coloration and pattern of the snake blend in with aquatic vegetation, concealing this predator from potential prey.
Anacondas are ambush predators. They immobilize and kill their prey by using their jaws to hold on the prey while coiling their bodies around the animal and constricting until it dies from suffocation or other crushing injuries. Prey is swallowed whole (Mattison, 2006) The list of potential prey items of an anaconda is extensive and varied and consists of birds, reptiles, mammals and the occasional fish. Known prey items include catfish, green iguanas, spectacled caiman, turtles, lizards, various aquatic birds, small rodents, capybaras, white tailed deer, and even other green anacondas (Rivas 1999).
Anacondas are not immune from predators. Neonate and juveniles are particularly prone to predation, and seem to suffer high mortality within their first year (Rivas 2000). Predators of small anacondas include crab-eating foxes, tegu lizards, crested caracaras, caimans and larger green anacondas (Rivas 1999, Rivas 2001, Mattison 2006).
Means of Introduction: Probable pet release or escape.
Status:
Not established as far as known.
Impact of Introduction: Unknown.
Remarks:
References
Areste, M. and R. Cebrian. 2003. Snakes of the World. Sterling Publishing Co., Inc. New York 256 pp.
Mattison, C. 1986. Snakes of the World. Facts on File Publications. New York, New York. 190 pp.
Mattison, C. 2006. Snake. D.K. Publishing, Inc. New York. 192pp.
Rivas, J. A. 1998. Iguana iguana (Green Iguana): Juvenile predation. Herpetological Review 29 (4): 238-239.
Rivas, J. A., J. B. Thorbjarnarson, M. C. Munoz and R. Y. Owens. 1999. Eunectes murinus: Caiman predation. Herpetological Review 30(2): 101.
Rivas, J. A. 2000. Life history of the green anaconda (Eunectes murinus) with emphasis on its reproductive biology. Ph.D. thesis, University of Tennessee, Knoxville.
Rivas, J. A. and R. Y. Owens. 2000. Eunectes murinus (Green anaconda): Cannibalism. Herpetological Review 31(1): 45-46.
Rivas, J. A., R. Y. Owens and P. P. Calle. 2001. Eunectes murinus: Juvenile predation. Herpetological Review 32 (2): 107-108.
Author: Denise R. Gregoire
Revision Date: 1/1/2007 Citation for this information:
Denise R. Gregoire. 2009. Eunectes murinus. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.
<http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=2636> Revision Date: 1/1/2007
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