The 10 Largest Snakes in South America

There are 600 to 700 snake species in South America, and 60 to 70 of them are venomous. However, the majority of the largest snakes in South America are not venomous. Many species of snakes use constriction, applying pressure via loops of their trunk, to subdue and kill their prey. Continue reading to learn more about the 10 largest snakes in South America by weight.

10. Emerald Tree Boa

True to its name, the emerald tree boa (Corallus caninus) is bright green, with delicate white markings. Emerald tree boas grow up to 6 feet long and weigh between 2 and 4 pounds. As juveniles, their coloring ranges from bright red to orange, turning green with age. These boas live in Brazil, Peru, Venezuela, Colombia, Guyana, and Suriname. They spend most of their time in trees, preying on birds, reptiles, amphibians, and small mammals. 

9. Brazilian Smooth Snake

The Brazilian smooth snake (Hydrodynastes gigas) grows up to 9 feet long and weighs 3.5 to 4.4 pounds, with some individual females weighing up to 10 pounds. They have light tan bodies with chevron-patterned dark brown to black stripes. Brazilian smooth snakes live throughout many parts of South America, especially humid rainforests and wetlands. Their diet primarily consists of fish and frogs.

8. Tiger Rat Snake

The nonvenomous tiger rat snakes (Spilotes pullatus) live throughout Central and Northern South America. They grow up to 10 feet long and weigh up to 4.9 pounds. Their coloring ranges from bright yellow to dull tan with black stripes. Tiger rat snakes spend most of their lives in the trees but occasionally come to the ground to hunt. They are opportunistic hunters and will prey on anything from small mammals to birds.

7. Rainbow Boa

One of the largest snakes in South America is the rainbow boa (Epicrates cenchria). They grow up to 6 feet long and weigh between 8 and 9 pounds. Rainbow boas live mostly in hot, humid forests, although they are occasionally found in open lands. Their native habitat ranges from Venezuela to the Amazon River basin. Like other constrictors, they kill their prey by squeezing it to death before swallowing it whole. Typical prey include birds, rodents, amphibians, and reptiles.

6. South American Bushmaster

The South American bushmaster (Lachesis muta) is the longest venomous snake in the western hemisphere. They measure up to 12 feet in length and weigh 6.6 to 11 pounds. As pit vipers, their mouths contain impressive, venom-delivering fangs and heat-sensing pits. Most of their bodies are copper-colored, with pale undersides and black markings. When threatened, they coil up and shake their tail, which lacks a rattle, as a warning.

5. Fer-de-lance

Fer-de-lance snakes (Bothrops) comprise 48 species native to Central and South America. They are pit vipers, which means they have heat-sensing loreal pit organs. Fer-de-lances live in northern South America, Colombia, Venezuela, Guyana, and Ecuador. When threatened, fer-de-lances famously stand their ground and may even bite in self-defense, and more deaths are attributed to them than any other venomous snake in the Americas. The largest species of fer-de-lance is the terciopelo (Bothrops asper), which measures up to 8.2 feet long and weighs up to 13 pounds. They are found in the northern regions of Colombia, Venezuela, Ecuador, and Peru.

4. Dark-spotted Anaconda

Dark-spotted anacondas (Eunectes deschauenseei) grow up to 9 feet long and weigh approximately 66 pounds. However, these measurements are not definitive as this species has seldom been studied. They get their name from the dark blotches that cover most of their body, which have a base color of olive green to yellow-brown. Dark-spotted anacondas are often found in waterways and semi-aquatic environments.

3. Yellow Anaconda

The yellow anaconda (Eunectes notaeus) measures 8 to 12 feet, with females measuring up to 15 feet. They usually weigh 55 to 77 pounds, with the largest weighing up to 121 pounds. These snakes spend most of their time hunting in wetlands, shallow lakes, and ponds. Like other constrictors, they use their massive bulk to overpower and suffocate prey. Yellow anacondas live in Paraguay, Uruguay, Bolivia, Brazil, and Argentina. 

2. Boa Constrictor

Boa constrictors (scientific name also Boa constrictor) are heavy-bodied snakes; the largest can weigh more than 100 pounds and measure up to 13 feet long. Some grow even longer; there are unverified reports of boa constrictors in captivity reaching up to 18 feet, though most confirmed individuals are significantly shorter. These snakes live throughout South America, where they spend most of their time in or around rivers and lakes. Because of their size, boa constrictors can hunt medium-sized prey, like wild pigs and deer.

1. Green Anaconda

The green anaconda (Eunectes murinus) is the largest snake in the world, while the reticulated python (Malayopython reticulatus) is the longest. On average, green anacondas measure 20 feet long and weigh 70 to 150 pounds. The largest confirmed green anaconda specimen was 27.7 feet long and weighed over 500 pounds. There are unverified reports of some green anacondas measuring up to 33 feet long; however, these measurements have not been confirmed by scientific authorities.