The biggest snakes in the world

How we ranked them

The list is ordered by the longest specimen that someone measured and reported in a way that can be checked: a Guinness-verified measurement, a museum specimen, or a snake measured in a published study^1,2,11. That rules out a surprising number of famous figures. When Barker and colleagues reviewed the maximum lengths claimed for pythons in 2012, they found that many were “unexplained”, presented without a source or a specimen, or rested on measurements of doubtful validity; the largest captive reticulated python they could confirm was “Colossus” of Pittsburgh Zoo at 6.35 m, and the largest captive Burmese python “Baby” at 5.74 m². Museum specimens in Copenhagen and Basel have since been measured at 7.10 m and 6.38 m². Murphy and Henderson devoted a whole book to the stories of giant anacondas and pythons and the evidence behind them¹⁷.

Measuring a giant snake is harder than it sounds. A live snake coils and resists, a dead one stretches, and skins stretch most of all, which is why a 4.45 m boa skin is taken to mean a snake of about 4.55 m, not more¹². Guinness notes that the 7.22 m Sulawesi python, measured awake, would measure perhaps 10–15% longer under anaesthesia, when a snake fully relaxes¹. Even in the biggest species, giants are rare: reticulated pythons harvested in Sumatra averaged 2.5–3.1 m from snout to vent¹⁸, and a growth model fitted to 200 captive Burmese pythons gave an average adult length of only 2.4 m².

The longest snake: the reticulated python

The reticulated python of South-East Asia is the longest snake in the world. The longest wild snake ever reliably measured was a female from Maros, Sulawesi, 7.22 m long and 96.5 kg, measured in January 2026¹. A captive reticulated python, Medusa, measured 7.67 m¹. The often-repeated 10 m python killed on Sulawesi in 1912 was never verified¹. Only a tiny fraction of wild snakes come close: of more than 7,000 reticulated pythons harvested in Indonesia and Malaysia, only 50 exceeded 4.5 m from snout to vent¹⁸.

The Central African rock python, Africa’s largest snake, has a reported maximum of 7.5–7.6 m, but most adults are 3–5 m^3,4,5. The Burmese python is third: the longest wild one, a 5.79 m female, was caught in Florida’s Big Cypress National Preserve in 2023, and a captive female measured 5.74 m^6,7. Female Burmese pythons grow up to 1.5–1.8 m longer than males, and the heaviest wild ones weigh about 97.5 kg⁸. In India, pythons measured in Keoladeo National Park reached 4.3 m¹⁴.

The heaviest snake: the green anaconda

The green anaconda of South America is shorter than the biggest pythons but far heavier for its length. In a seven-year study of 780 wild anacondas in the Venezuelan llanos, females averaged 3.1 m and 20 kg, no male was longer than 3.39 m, and the largest was a female of 5.21 m and 97.5 kg¹¹. Reports of 9–11 m anacondas have circulated for a century, and none near that size was found¹¹. Even experts have been fooled by the family resemblance: a famous 5.64 m “boa constrictor” killed in Trinidad in the 1940s turned out to be a green anaconda¹². The boa constrictor itself is generally 2–3 m, and animals over 3.5 m are rare¹².

The longest venomous snakes

The king cobra is the longest venomous snake. Adults are commonly 3–3.6 m, the species is reported to reach 5.5 m, and the longest ever measured, 5.71 m, came from the Malay Peninsula^9,10. In Africa the black mamba is the longest venomous snake, usually 2–3 m and reaching about 4.5 m, although snakes over 3.8 m are rare¹³.

Australia’s giants

Australia’s longest snake is the scrub or amethystine python of north-east Queensland. Enormous lengths are often quoted for it, but in a field study of the species the largest males measured 3.76 m from snout to vent and weighed 11 kg, with adult males ranging from 1.3 m and 0.3 kg to that size¹⁵. Males grow much larger than females in this species, which is unusual among pythons¹⁵. The more widespread carpet python is mostly about 2 m long and rarely over 2.5 m, although some reach 4 m¹⁶.

Are the biggest snakes dangerous?

None of the giant constrictors is venomous, but the largest can kill. A 2025 review found 17 incidents in Indonesia between 1927 and 2025 in which reticulated pythons attacked or swallowed people, 13 of them fatal, involving snakes reported at 5–8 m¹⁹. Wild Burmese pythons rarely attack people; the few deaths recorded in Florida were caused by captive snakes⁸. A review of the scientific literature found no recorded case of an anaconda eating a person²⁰. Keep well away from any large snake, never try to handle one, and seek medical care for any bite.