Anacondas are members of the boa family of snakes along with pythons. They fall into the genus Eunectes in which four anaconda species are found. All of the four species are commonly found in or around water and are among the largest snake species on the planet. Anacondas kill their prey by constriction and are not venomous.
One of the most commonly known species, the green anaconda is the largest snake in the world. It can grow to 30 feet in length and weigh up to 550 lbs. The snake is broad and powerful and spends much of its time in the water. It lives in the wetland regions of South America and hunts large prey such as pigs and deer, striking with high speed from the water.
The yellow anaconda is a much smaller relative of the green species. It grows to an average of 10 feet in length and also has a thick, powerful body. Its main coloring is yellow to light green with brown to black mottled blotches running the length of its body. It lives in the forested wetlands in South America and ranges further south than the green anaconda and not as far north.
The dark-spotted anaconda is much the same size as the yellow variety but is browner in color and has darker markings. It is less common than the green and yellow species, living in small populations in northern Brazil and French Guiana. Like the other species of anaconda. it lives in swampy wetlands spending much of its life in the water. Like all anacondas, it is a member of the boa family and retains small, spur-like appendages on its tail which are the remnants of legs.
The Bolivian anaconda is very similar to the green variety in size and appearance, but is less widespread. It lives only in Bolivia with a slight, unconfirmed possibility of some population crossover in Brazil. As an adaptation to its semi-aquatic lifestyle, like other anacondas, its nostrils and eyes are high on the snakes skull, so it can remain mostly submerged for long periods. The snake gives birth to live young as do all the anaconda species.