Member of the boa family, South America’s green anaconda is, pound for pound, the largest snake in the world. Although the reticulated python can reach slightly greater lengths, the enormous girth of the anaconda makes it almost twice as heavy.
Green anacondas typically grow to around 20 feet (6 meters) in length and weigh around 330 lbs (149 kgs). However, they can grow to more than 30 feet (9 meters) in length, weigh over 500 lbs (226 kgs), and measure 30 centimetres (12 inches) in diameter. Females are significantly larger than males and green anacondas exhibit the greatest size difference between the sexes of any terrestrial vertebrate. Other anaconda species, all from South America and all smaller than the green anaconda, are the yellow, dark-spotted, and Bolivian varieties.
As the name suggests, the green anaconda is olive green in colour, and contains black smudges running across the entire length of its body. The head of the green anaconda snake is narrower than the rest of its body and is characterized by a distinctive orange-yellow striping on either side. Apart from the above mentioned physical features, the green anacondas also have scales. There are claw-like spurs located on either side of the cloaca (the cavity into which the genito-urinary and digestive tracts of the anaconda snakes empty). This is the only region of the green anaconda snake’s body that does not have scales, and which emits a musk with a foul odour that is poisonous to small organisms. Perhaps this is a mode whereby the green anaconda snake prevents leeches and ticks from attaching themselves to its cloaca. Analogous with the fingerprint of a human, the pattern of scales found along the yellow and black underside of the lower tail of the green anacondas is unique to each anaconda snake.
Green anacondas dwell mainly in the marshes and swamps in the Amazon and Orinoco basins of northern South America. They are cumbersome on land, but stealthy and sleek in the water. Their eyes and nasal openings are on top of their heads, allowing them to lay in wait for prey while remaining nearly completely submerged.
They reach their monumental size on a diet of wild pigs, deer, birds, turtles, capybara, caimans, and even jaguars. Anacondas are nonvenomous constrictors, coiling their muscular bodies around captured prey and squeezing until the animal asphyxiates. Jaws attached by stretchy ligaments allow them to swallow their prey whole, no matter the size, and they can go weeks or months without food after a big meal.
Green anacondas are ‘ovoviviparous,’ which means that the females carry the eggs within their bodies until the babies are ready to hatch. Females give birth to two to three dozen live young. Baby snakes are about 2 feet (0.6 meters) long when they are born and are almost immediately able to swim and hunt. From birth to adulthood, the green anaconda undergoes a dramatic 500-fold increase in mass, a greater increase than any other snake species. Their lifespan in the wild is about ten years.
Green anacondas continue to interest and amaze people the world over but they face a number of threats, which could have a significant impact on their population. They are hunted, both legally and illegally, in many parts of its range for its skins and for sale in the growing, illegal pet trade. They are also the victims of human prejudice and ignorance. Local people kill thousands of anacondas every year under the pretext of protecting livestock, pets or even people. However, in many cases, a widespread fear and dislike of snakes results in individuals of this species being persecuted, even when found in remote areas. Habitat loss and degradation are also threatening this species, and even in areas where habitat protection exists, a lack of enforcement is allowing illegal deforestation to occur.