The Common Anaconda

The Anaconda is the heaviest known snake species and lives in South America. This non-venomous boa’s name ‘Eunectes murinus’ is derived from the Greek word ‘Ευνήκτης’, which means ‘good swimmer’, and the Latin word ‘murinus’, which means ‘he who predates on mice’. These huge, misunderstood snakes have become a symbol of horror in pop culture.

The AnacondaCredit: LA DawsonCredit: LA Dawson

The Anaconda's Appearance

Although the Reticulated Python is longer, the Anaconda is the heaviest snake in the world, and can reach lengths of more than 6.6 metres (22 feet) long, with unconfirmed reports of Anaconda reaching up to 35-40 feet long. The longest and heaviest scientifically recorded Anaconda was a female who was 5.21 metres (17 feet 1 inch) long and weighed 97.5 kilograms (215 pounds).

Common names for the Anaconda also include Green Anaconda, Common Anaconda and Water Boa, as well as ‘mata-toro’, meaning ‘bull killer’ in Spanish. The Anaconda has olive coloured scales that are covered with black blotches along the entirety of its body. Its head is narrow, and has distinctive stripes on either side, ranging in colour from orange to yellow. The Anaconda’s eyes are up high on its head, which allows for the snake to see out of the water when swimming through the water.

The Anaconda's Habitat

The Anaconda is found in South America, in countries including Venezuela, Ecuador, Peru, Bolivia, Brazil and Columbia. Anaconda live near water, such as in swamps, marshes and slow-moving streams, mainly within the tropical rainforests found in the Amazon and Orinoco basins. Anaconda don’t move well on land, travelling rather awkwardly, but through water they are fast and stealthy. Because of the position of their eyes and nasal cavities, they can wait for their prey with their bodies nearly completely submerged underwater.

The Anaconda's Behaviour and Feeding Techniques

The Anaconda is primarily nocturnal, and spends most of its life in or around water.  While they can reach fast speeds at different depths of water, they mainly float on top of the surface of the water, with their snout poking out of the water. When prey passes by, the Anaconda will lunge at it and catch it with its jaws before coiling its body around the animal, constricting its powerful muscles throughout its body, until it has successfully suffocated the animal. Anaconda will eat anything it can overpower, including fish, birds, mammals and other reptiles. Larger Anaconda can even consume prey such as tapir, deer and caiman, but it is rare. There are folk stories of Anaconda being man-eaters, but there is little evidence to support it.

Anaconda also participate in cannibalism, with larger females consuming smaller males. Scientists are unsure as to why this occurs, but theories suggest it could be a result of the dramatic sexual dimorphism in the species, and the possibility that a female anaconda just requires additional food intake after breeding to sustain the long period of gestation. With the mating male nearby, he simply provides the opportunistic female with an easy source of nutrition.

The Anaconda's Breeding and Mating Rituals

Other than when the mating season occurs between April and May, Anaconda live and travel solo. When it comes time to mate, the female Anaconda will leave a trail of pheromones so that males can locate her, although it is still unclear to scientists how male Anaconda track the scent from the female. There is a theory that females release an airborne stimulant, as there have been observations of female Anaconda who remain motionless while many male Anaconda move towards them from multiple different directions.

Usually there are multiple males trying to mate with a single female, which result in a cluster, referred to as a ‘breeding ball’, in which up to 12 male Anaconda will wrap themselves around the same female in an attempt to mate with her. These group orgy sessions can last from 2-4 weeks, acting as a slow-motion wrestling match, with each male fighting for the right to mate with the female. When the largest and strongest male is the victor, the male will mate with the female by coiling his tail around the female. This whole courtship and mating process takes place almost exclusively in water.

The gestation period then lasts between 6-7 months. The female will then give birth to live young, usually between 20-40 offspring. After the birth, females can lose up to half their body weight. Anaconda babies are around 70-80 centimetres (27-31 inches) and receive no care from their mother. They are left to fend for themselves, and because of their small size, often fall prey to other animals. Below is a video documenting an Anaconda giving birth:

An Anaconda Giving Birth

Because of their large size, Anaconda have become plagued with the image of a terrifying man-eating , vicious snake. But there is limited evidence to suggest that these large, misunderstood snakes regularly attack humans. These graceful, majestic creatures really are the king of the South American rainforests, and deserve our respect and protection.