What is the heaviest species of snake?

The green anaconda is the heaviest living species of snake. It is not usually the longest—that distinction belongs to the reticulated python—but its exceptionally broad, muscular body gives it greater mass than other living snakes in typical wild comparisons.

Known scientifically as Eunectes murinus, the green anaconda lives in rivers, swamps, and wetlands across tropical South America. Females are much larger than males, a striking example of sexual size dimorphism. Large females commonly reach several metres in length, while verified weights vary greatly with body condition, recent meals, and whether the animal was measured in the wild or captivity.

The green anaconda is a non-venomous constrictor. It ambushes prey from the water, seizing animals such as fish, birds, capybaras, caimans, and occasionally other substantial mammals. Its eyes and nostrils sit high on the head, allowing it to watch and breathe while mostly submerged.

Popular stories of extraordinarily long anacondas are often unverified. Reliable measurements matter because stretched skins, estimates, and exceptionally full stomachs can greatly exaggerate a snake’s apparent size.