Variant names: Boiúba, Boiúna, Camoodi,
Cobra-grande, Controller, Ibibaboka, Lampalagua
(in Argentina), Matatora (Spanish,
“bull-killer”), Sachamam a, Sucuriju gigante
(Portuguese, “giant anaconda”), Yaurinka.
Physical description: Length, 40–150 feet. Darkchestnut
color. Diameter, more than 2 feet 6
inches. Weight, up to 5 tons. Triangular head.
Two horns above the eyes. Large eyes glow phosphorescent
blue at night. Off-white spots on belly.
Behavior: Semiaquatic. A swift swimmer.
Creates a huge wake.
Tracks: Wide furrow through the swamp,
with trees pushed up.
Distribution: Amazon River basin, Brazil; less
credible reports are from Argentina, Venezuela,
Significant sightings: Explorer Percy H. Fawcett
shot a 62-foot anaconda on the Rio Abuna,
Acre State, Brazil, near the Peruvian border, in
January 1907. However, its largest diameter was
12 inches, which seems small for the length.
Fr. Victor Heinz saw a giant water snake on
the Amazon near Alenquer, Brazil, on October
29, 1929. Its blue-green, phosphorescent eyes
were at first mistaken for a riverboat’s lights.
A photo made into a postcard shows a 105-
foot snake with shining eyes that was reportedly
killed by the Brazilian Boundary Commission
on the frontier with Venezuela in 1932. It was
said to be 4 feet thick. No hint of the snake’s
size is provided, though three out-of-focus humans
can be seen in the background.
Another photo taken in 1948 or 1949 by
Joaquim Alencar shows a huge snake, variously
said to be 115 or 147 feet long, floating on the
Rio Abuna, Acre State, Brazil.
In 1977, Amarilho Vincente de Oliveira saw
a giant snake with horns and greenish eyes on a
tributary of the Rio Purus, Brazil.
Present status: The record length for an anaconda
of 37 feet 6 inches, reported in 1939 or
1940 by Robert Lamon, is not universally accepted.
John Murphy and Robert Henderson
point out that enormous snakes have fewer
places in which to hide from predators, and
their great size would cause problems with
maintaining blood pressure in the tail. After
surveying the ratio of minimum adult length to
the record length of many snake species, Peter
Pritchard has concluded that the maximum
length of a snake is 1.5–2.5 times its shortest
adult length; small anacondas are 10–12 feet
long, making the largest theoretical length 30
feet. Aaron Bauer estimates that Fawcett’s 62-
foot snake had to have been at least 30 inches in
diameter and spend virtually all its time in the
(1) Skins of normal-sized Anacondas
(Eunectes murinus) are often dried and
stretched, resulting in a much greater
length. Even a skin that is not stretched can
be 10–20 percent longer than the live snake.
(2) Field estimates are often unreliable,
especially for snakes that are partially
(3) An unknown species of anaconda that
normally attains such lengths.
(4) Reports of horns might be caused by
protruding eyes, fleshy outgrowths caused
by an injury, or barlike markings on the
Reports of giant anacondas date back as far as the discovery of South America, when sightings of anacondas upwards of 50 metres (150 feet) began to circulate amongst colonists, and the topic has been a subject of debate ever since among cryptozoologistsand zoologists. Anacondas can grow to sizes of 6 metres (20 ft) and beyond, and 150 kilograms (330 lbs.) in weight. Although some python species can grow longer, the anaconda, particularly the green or common anaconda, is the heaviest and largest in terms of diameter of all snakes, and it is the second-longest extant snake in the world behind thereticulated python. The longest reputably-measured and confirmed anacondas are about 7.5 metres (25 feet) long. Lengths of 50–60 feet have been reported for this species, but such extremes lack verification. The only real reliable claims that can be found describe measured anacondas ranging from 26 to 39 feet, although these remain unverified.
The first recorded sightings of giant anacondas were from the time of the discovery of South America, when early European explorersentered the dense jungles and claimed to have seen giant snakes measuring up to 18 metres (59 ft) long. Natives also reported seeing anacondas upwards of 10.5 metres (34 ft) to 18 metres (59 ft). Anacondas above 7 metres (23 ft) in length are rare. TheWildlife Conservation Society has since the early 20th century, offered a large cash reward (currently US$50,000) for live delivery of any snake of 9 metres (30 ft) or more in length, but the prize has never been claimed, despite the numerous sightings of giant anacondas. In a survey of 780 wild anacondas in Venezuela, the largest captured was 5 metres (16 ft) long. A specimen measured in 1944 exceeded this size when a petroleum expedition in Colombia claimed to have measured an anaconda which was 11.4 metres (37 ft) in length, but its claim has never been proven.
Scientist Vincent Roth claimed to have shot and killed a 10.3 metres (34 ft) specimen, but like most other claims, it lacks sound evidence. Another claim of a large anaconda was made by British adventurer Percy Fawcett. Following his 1906 survey of the Bolivia/Brazil border, Fawcett wrote that he had shot an anaconda that measured some 19 metres (62 ft) from nose to tail. Once published, Fawcett’s account was ridiculed. Decades later, Belgian cryptozoologist Bernard Heuvelmans came to Fawcett's defence, arguing that Fawcett's writing was generally honest and reliable. In Fawcett's favour is the fact that he was conducting a field survey and would have had at his disposal suitable measuring instruments. In an earlier part of his diary, he suspects a claim that an anaconda of 17.67 m. (58 ft.) was discovered was "exaggerated" until his own discovery of the larger snake.
Historian Mike Dash writes of claims of even larger anacondas, alleged to be as long as 45 metres (148 ft), with some of the sightings supported with photos (although the photos lack scale). Dash noted if reports of a 18 metres (59 ft) anaconda strains credulity, then a 120 feet (37 m) long specimen would be an impossibility.
Joel Mckenzie-Rogers has reported that he has seen a large snake.
On the episode "Amazon Assassins" of River Monsters, Jeremy Wade was trying to find and catch a large Arapaima when locals told him about the "Cobra Grande", a giant snake different from the anaconda. They showed him a burrow which appeared to be made by the snake but he did not find the snake and instead focused on finding the Arapaima. During an expedition in the Peruvian Amazon in 2009, a Belfast father and his son claim to have captured a giant anaconda on camera. One interpretation of the photograph claims the "snake" has tentacles; as a result one alternative explanation is that it is an unknown species of giant caecilian, seeMinhocão.