The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Eunectes notaeus
Eunectes notaeus
(Yellow Anaconda)

Copyright Info
Eunectes notaeus Cope, 1862

Common name: Yellow Anaconda

Taxonomy: available through www.itis.govITIS logo

Injurious: This species is listed by the U.S. Fish and Wildlife Service as injurious wildlife.

Native Range: The Yellow Anaconda occurs in southern South America, including the Pantanal in Bolivia and Brazil, and south through the Paraguay and Parana River Basins in Paraguay and Argentina (Reed and Rodda, 2009).

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Eunectes notaeus are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
AR200420051Lower St. Francis
FL200620214Apalachee Bay-St. Marks; Big Cypress Swamp; Everglades; Myakka

Table last updated 6/16/2024

† Populations may not be currently present.

Ecology: The Yellow Anaconda lives mainly in water and appears to be restricted to swampy, seasonally flooded, or riverine habitats (Reed and Rodda, 2009).

The Yellow Anaconda is a generalist carnivore, preying mainly on animals found in wetland and riparian areas throughout its range. Its diet consists of birds, bird eggs, small mammals, turtles, lizards, other snakes, occasional fish or fish carrion, capybara, and caimans (Reed and Rodda, 2009). The Yellow Anaconda is considered an ambush hunter and constrictor. The digestive system is relatively slow and the Yellow Anaconda may eat only every few days or months, depending on the size of the last prey item. The Yellow Anaconda can survive long periods without prey (Reed and Rodda, 2009).

An adult Yellow Anaconda has few natural predators. Humans are the main predator and it is hunted primarily for its skin, although there are varying numbers imported each year for the pet trade. Predators of juveniles and the occasional adult include Crab-eating Foxes (Cerdocyon thous), tegu lizards (Tupinambis merianae), Spectacled Caimans (Caiman crocodilus), larger anacondas (Eunectes), felids (cats), canids (dogs), procyonids (raccoon family), mustelids (weasel/skunk family), herons, and raptors such as the Crested Caracara (Polyborus plancus) (Reed and Rodda, 2009).

The Yellow Anaconda is a solitary animal, except in breeding season (April and May). Yellow Anacondas have been known to form breeding balls, consisting of one female and multiple males. After a 6-month gestation period, the females give birth to fully developed live young. There is great variation in the literature about litter size, but Reed and Rodda (2009) believed the best estimate for wild individuals was 7–42 with an average of 19.5. These young immediately are able to live on their own. Young anacondas reach sexual maturity at 17 to 29 months old. In captivity, Yellow Anacondas have lived to more than 20 years of age (Reed and Rodda, 2009).

Means of Introduction: Released pets.  Yellow Anancondas are available in the pet trade but are quite expensive.

Status: Unknown. The remote location of these specimens and finding three in a approximately 6 months from the same area is worrisome, but no individuals have been reported from the area since 2008.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

References: (click for full references)

Krysko, K.L., and 12 others. 2011. Verified non-indigenous amphibians and reptiles in Florida from 1863 through 2010—Outlining the invasion process and identifying invasion pathways and stages. Zootaxa 3028:1—64.

Reed, R.N., and Rodda, G.H. 2009. Giant constrictors: biological and management profiles and an establishment risk assessment for nine large species of pythons, anacondas, and the boa constrictor: U.S. Geological Survey Open-File Report 2009–1202, 302 p. (Also available at http://pubs.usgs.gov/of/2009/1202/pdf/OF09-1202.pdf.)

Author: Fuller, P.

Revision Date: 7/31/2023

Citation Information:
Fuller, P., 2024, Eunectes notaeus Cope, 1862: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2576, Revision Date: 7/31/2023, Access Date: 6/16/2024

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [6/16/2024].

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