Anacondas are large, semi-aquatic, non-venomous constrictors found in tropical South America. Known for their impressive size, they inhabit swamps, marshes, and slow-moving rivers, ambushing prey. The term “anaconda” commonly refers to the largest species within the Eunectes genus, well-adapted to aquatic environments.
The Green Anaconda: Earth’s Heaviest Snake
The green anaconda, including the southern (Eunectes murinus) and northern (Eunectes akayima) species, is the world’s heaviest snake due to its substantial girth. They inhabit the Amazon and Orinoco basins, thriving in wetlands and flooded savannas. Their eyes and nostrils are positioned on top of their heads, allowing them to remain almost entirely submerged while waiting for prey. Though cumbersome on land, these snakes are agile and stealthy in water. Their diet includes fish, birds, mammals, and reptiles, which they overpower by constriction.
Documented Lengths and Verified Records
Scientifically verified lengths for green anacondas typically fall between 5 and 6 meters (16 to 20 feet). Measuring wild anacondas is challenging due to their elusive nature, remote habitats, and the difficulty in accurately measuring a powerful, live snake. Specimens exceeding 7 meters (23 feet) are rare and often lack scientific verification.
One accurately measured green anaconda was a female at 5.21 meters (17 feet 1 inch) and 97.5 kilograms (214 pounds), recorded by Dr. Jesús Antonio Rivas. Recent discoveries of northern green anacondas (Eunectes akayima) include individuals up to 6.3 meters (20.7 feet). Anecdotal accounts suggest larger sizes, potentially 7.5 meters (24.6 feet), though these remain unconfirmed.
Beyond the Records: Dispelling Common Myths
Claims of anacondas reaching extreme lengths, such as 9 to 15 meters (30 to 50 feet), are widespread but unsubstantiated. These tales often stem from misidentification, anecdotal evidence, or skin stretching during tanning. Biological limitations also make such immense sizes improbable. Snake metabolism, prey availability, and physical demands restrict their growth.
For decades, the Wildlife Conservation Society has offered a reward for any verifiable live snake 9.1 meters (30 feet) or longer, a prize never claimed. This highlights the disparity between popular myths and actual observed maximum sizes. Scientifically verified green anacondas do not approach the colossal figures often depicted in folklore or media.
Other Anaconda Species and Their Sizes
While the green anaconda garners attention for its size, three other recognized anaconda species exist, though considerably smaller. These include the yellow anaconda (Eunectes notaeus), found in southern South America, typically reaching 3 to 4.6 meters (10 to 15 feet), with an average adult length of 3.7 meters (12 feet).
The Bolivian anaconda (Eunectes beniensis), primarily found in Bolivia, can grow up to 4 meters (13 feet). The dark-spotted anaconda (Eunectes deschauenseei), native to parts of northern Brazil and French Guiana, is the smallest, with adult females typically measuring 1.2 to 2.31 meters (4 to 7.5 feet). These species do not rival the green anaconda in overall length or mass.