The natural world is home to an astonishing array of creatures, and among the most captivating are snakes, particularly those of immense size. Determining the world’s “biggest” snake, however, involves considering different metrics, primarily whether size is measured by length or by weight.
The Green Anaconda: Earth’s Heaviest Serpent
The green anaconda (Eunectes murinus) holds the distinction as the world’s heaviest and largest snake by mass. Native to South America, this formidable reptile typically inhabits the Amazon and Orinoco river basins, as well as the flooded Llanos grasslands of Venezuela. Adult female green anacondas are considerably larger than males, with average lengths around 4.6 meters (15 feet 1 inch) and weights ranging from 30 to 80 kilograms (66 to 176 pounds). While unverified claims exist of much larger specimens, a notable confirmed female measured 5.21 meters (17 feet 1 inch) long and weighed 97.5 kg (214 pounds 15 ounces). The sheer bulk of a green anaconda, particularly its girth, distinguishes it, making a 5.2-meter (17-foot) green anaconda comparable in mass to a 7.4-meter (24-foot) reticulated python.
Life in the Anaconda’s Domain
Green anacondas are semi-aquatic, preferring shallow, slow-moving waters such as swamps, marshes, lagoons, and rivers within tropical rainforests and savannas. Their eyes and nasal openings are positioned on top of their heads, allowing them to remain almost entirely submerged while waiting for prey. This adaptation makes them stealthy predators in their watery habitats. They are ambush predators, often lying in wait until an unsuspecting animal comes within striking distance.
Their diet is varied and includes large prey such as capybaras, caimans, deer, wild pigs, and even birds and fish. Once they capture prey, green anacondas, like other boas, are non-venomous constrictors. They coil their muscular bodies around the animal, squeezing until it can no longer breathe. Their jaws are designed to unhinge, enabling them to swallow their prey whole, even if it is larger than their head. Following a large meal, anacondas can go for weeks or even months without needing to eat again, due to their slow metabolism.
Other Giants of the Serpent World
While the green anaconda reigns as the heaviest, the reticulated python (Malayopython reticulatus) holds the record for the world’s longest snake. This species is native to South and Southeast Asia. Reticulated pythons typically average between 3 to 6 meters (10 to 20 feet) in length, with some individuals exceeding 7 meters (23 feet). The longest confirmed specimen measured 7.67 meters (25 feet 2 inches) and weighed 158.8 kilograms (350 pounds).
Another large constrictor is the Burmese python (Python bivittatus), native to Southeast Asia. These snakes typically grow to between 3 and 5 meters (10 and 16 feet) in length and can weigh up to 90.7 kg (200 pounds). While impressive in size, they do not generally reach the extreme lengths or weights of the reticulated python or the green anaconda, respectively.
Distinguishing the Giants
Accurately measuring wild snakes presents significant challenges, making precise record-keeping difficult. Verified length records require careful measurement of a dead or heavily sedated specimen using a steel tape, preferably with witnesses and documented through publication or video. Unverified reports of exceptionally large snakes, particularly anacondas, often exceed scientifically confirmed measurements.
Comparing living snakes to prehistoric giants provides further context. The extinct Titanoboa cerrejonensis, which lived approximately 58 to 60 million years ago, was considerably larger than any modern snake. Estimates suggest Titanoboa could reach lengths of about 12.8 to 14.3 meters (42 to 47 feet) and weigh between 730 to 1,135 kg (1,610 to 2,500 pounds). This ancient serpent highlights the immense scale that snakes once achieved, far surpassing the largest living species today.