Snake Species · Amazon & Orinoco basins
Green Anaconda
Heaviest snake on Earth — apex predator of South American wetlands.
By the WARN Research & Conservation TeamChecked against IUCN Red List & CITES sourcesLast updated
In brief
The Green Anaconda is the heaviest snake on Earth — bulky aquatic constrictor of Amazon and Orinoco wetlands including Brazil and Colombia, WARN partner regions. Its defining trait is extreme sexual size dimorphism with females reaching 5–6 m and over 200 kg. Apex predator of South American floodplains; see WARN's dedicated anaconda wildlife guide.
Green Anaconda: At a Glance
| Origin | Amazon & Orinoco basins |
|---|---|
| Size | Very large (5–6 m+) |
| Typical length | 4–6 m (13–20 ft) typical females; 100–200+ kg body mass — heaviest living snakes |
| Lifespan | 15–20 years (grass snake); 20–30 years (anaconda) |
| Scales & pattern | Olive green ground with dark oval dorsal blotches; orange or yellow underside. Smooth scales with dark eye stripes. Skin appears rougher than pythons due to scale texture. Darkens after shed; pale eyes precede moulting. Aquatic adaptation shows in eyes and nostrils positioned dorsally on the head. |
| Temperament | Aquatic constrictor, heavy-bodied |
| Conservation note | Wild green anacondas belong in Amazon and Orinoco floodplains — not domestic enclosures. Zoological collections maintain specimens under expert protocols. Support wetland protection in Brazil and Colombia; fishermen persecution and illegal collection threaten regional populations. |
History & Origins
Green anacondas inhabit swamps, rivers, flooded forest and oxbow lakes of the Amazon and Orinoco basins — including Brazil and Colombia where WARN partners work on rainforest conservation. Females are substantially larger than males — among the most extreme sexual size dimorphism in vertebrates. They ambush capybara, caiman, deer and fish at water's edge, constricting prey underwater. Green anacondas give birth to 20 to 40 live young. Hollywood exaggerations of 30 m anacondas exceed verified records — 6 m and 200 kg represent realistic maxima. Fishermen kill anacondas on sight across the Amazon; habitat loss from dam construction and deforestation reduces floodplain habitat. WARN publishes a dedicated anaconda wildlife guide with full species detail beyond this library entry.
Green Anaconda Fun Facts
- Green anacondas are the heaviest snakes on Earth — not the longest, but the most massive.
- Females may be ten times heavier than males — extreme sexual size dimorphism.
- They can remain submerged for ten minutes while stalking prey at water's edge.
- Multiple males may coil in a breeding ball around a single large female during mating season.
Green Anaconda Common Health Issues
Conditions seen more often in this breed, and how owners and vets help manage them. This is general guidance, not veterinary advice — always speak to your vet.
Habitat loss
Dam construction, deforestation and wetland drainage in Brazil and Colombia reduce green anaconda floodplain habitat.
Care: Support Amazon and Orinoco wetland protection through WARN partner programmes. Oppose dam projects without environmental mitigation.
Persecution by fishermen
Amazon fishermen kill anacondas on sight, removing apex predators from aquatic ecosystems.
Care: Support community education on anaconda ecology. Tourism programmes in the Pantanal and Amazon generate income from live anacondas.
Illegal collection
Green anacondas are collected for zoos, film and the pet trade despite impracticality of home keeping.
Care: Never purchase anacondas for private keeping. Support in-situ conservation and responsible ecotourism in range countries.
Snakes keep ecosystems healthy
Snakes control rodents and serve as prey for raptors — yet persecution and habitat loss remove them silently. WARN publishes these guides to reduce fear-driven killing in Pakistan, Brazil, Colombia and beyond.
