These species belong to the genus Eunectes, known as anacondas, native to South America. They thrive in aquatic environments like swamps and rivers. Anacondas are renowned for their immense size, constricting hunting method, and solitary nature. E. murinus is the largest, while E. notaeus is distinguished by its yellow hue.

The species E. murinus, E. notaeus, E. deschauenseei, and E. Beniensis belong to the genus Eunectes, commonly known as anacondas. These species are native to South America. E. murinus, the Green Anaconda, is found in the Amazon and Orinoco basins across countries such as Brazil, Venezuela, Colombia, Ecuador, Peru, and Bolivia. E. notaeus, the Yellow Anaconda, is primarily found in the Paraguay River basin in countries like Paraguay, southern Brazil, Bolivia, and northeastern Argentina. E. deschauenseei, the Dark-spotted Anaconda, is more restricted to northeastern Brazil, particularly in the Pará and Amapá states. E. beniensis, the Bolivian Anaconda, is found in the Beni region of Bolivia.

Anacondas generally inhabit tropical and subtropical regions with warm, humid climates. They are frequently found in swamps, marshes, and slow-moving streams and rivers. These environments typically have dense vegetation and are prone to seasonal flooding, which the anacondas use to their advantage for hunting and camouflage.

As apex predators, anacondas play a crucial role in their ecosystems by controlling the populations of various prey species. They primarily feed on fish, birds, mammals, and occasionally other reptiles. Their semi-aquatic nature allows them to hunt both in water and on land. Anacondas exhibit adaptations such as powerful constriction ability and the capacity to stay submerged underwater for extended periods, aiding in their stealth and ambush hunting techniques.