With exquisitely patterned bodies, predatory strikes that accelerate faster than a fighter jet, and even a capacity for "flight," snakes are a fascinating group of reptiles. Some deserve attention for one feature in particular: their enormous size.
From boa constrictors to reticulated pythons, we share the planet with some incredible serpentine heavyweights. These predators are found across the globe, including southeast Asia, South America and the United States. But how big are the biggest snakes in the world? And what are the biggest extinct snakes in history?
Size can be tricky to measure accurately — particularly when it comes to long-dead species. Historic records can be difficult to verify, and snake skins can be stretched without much visible distortion, leading to overestimates, Patrick Campbell, senior curator of the reptiles collection at the Natural History Museum in London, told Live Science.
However, he said that “there are a few authenticated records” of giant snakes from around the world. Below is a sampling of these supersized serpents.
Here's a descending list of the world's biggest, heaviest and longest snakes, from the smallest of the serpent giants through to the largest to have ever existed — a behemoth the size of a Tyrannosaurus rex.
10. Central African rock python (up to 16.5 feet)
The Central African rock python (Python sebae) is Africa’s largest snake, according to Oregon Zoo. It’s highly adaptable and found throughout sub-Saharan Africa, where it is equally at home in savannah, forest and desert habitats. These pythons average around 9.8 to 16.5 feet (3 to 5 m) long, according to Animal Diversity Web (ADW).
Like Burmese pythons, Central African rock pythons can gulp down sizable prey including antelope and crocodiles. Occasionally, even humans are on the menu: there are several accounts of African rock pythons attacking and even partially consuming people. These snakes can swallow such large prey thanks to a set of highly flexible jaws, a trait they share with several other snake species. “Because they’re able to disassociate the upper and lower jaws when about to devour prey, they can often take in things which are much larger than their head sizes,” Campbell said.
9. King cobra (18.7 feet)
Rearing up to display its flared hood and venomous fangs, the king cobra (Ophiophagus hannah) cuts a threatening figure — and not just because its bite is powerful enough to kill an elephant. Native to Asia, king cobras can grow over 16 feet (5 meters) long, according to the Smithsonian’s National Zoo and Conservation Biology Institute The longest king cobra ever recorded was a captive snake that reached 18.7 feet (5.71 m) at London Zoo in the late 1930s, according to Guinness World Records — roughly the length of a shipping container. It was killed at the outbreak of World War II to prevent it from escaping into the city if the zoo was bombed.
Venomous snakes usually don’t grow to be giants. Their ability to immobilize their prey with a single bite means they typically don’t need to rely on size or strength to feed, Campbell said. However, king cobras are an “exception to the rule," he said, making them the longest venomous snake on Earth.
8. Burmese python (18.8 feet)
Burmese pythons (Python bivittatus) are one of 41 python species worldwide. Burmese pythons are native to Southeast Asia and start life in trees, but by adulthood their size forces them down to the ground. The largest recorded Burmese python was a captive snake named Baby, which measured 18.8 feet (5.74 m) long, according to Guinness World records. In the wild, these snakes regularly stretch to over 16 feet (4.9 m) long — large enough to hunt alligators.
The largest Burmese python ever found in Florida — where it is an invasive species — was caught in 2022. It weighed 215 pounds (97.5 kg) and was 17.7 feet (5.4 m) long.
As if that wasn’t impressive enough, researchers studying Burmese pythons in the Florida Everglades (where pythons that were initially imported as pets have become invasive) discovered that these snakes also have extraordinary homing instincts: Relocated pythons can follow their noses back home for over 20 miles, the researchers wrote in a 2014 study in the journal Biology Letters.
7. Cuban boa (up to 19.6 feet)
These iridescently scaled boas, endemic to Cuba, are the largest snakes in the Caribbean, according to the Lake District Wildlife Park. Weighing over 66 pounds (30 kilograms) and reaching up to 18.5 feet (5.65 m) long, according to researchers publishing in the journal Reptiles & Amphibians — some reports claim they can grow to more than 19.6 feet (6 m) — Cuban boas (Chilabothrus angulifer) spend much of their time coiled around tree branches or scouting for lizards and rodents on the ground.
Cuban boas also stand out thanks to their unique hunting methods: They are the only snakes known to hunt in packs. In 2017, researchers described these otherwise antisocial animals strategically teaming up to form a barrier at the mouth of a cave in a Cuban national park, blocking the flight path of roosting bats. This enabled the snakes to leap up and snatch the bats out of the air.
6. Indian python (up to 21 feet)
Possibly the species that inspired Kaa, the enigmatic talking snake from Rudyard Kipling’s "The Jungle Book," the Indian python’s (Python molurus) gargantuan size in story books is only a partial exaggeration: These snakes can grow to 20.9 feet (6.4 m) long and weigh almost 220 pounds (100 kg), according to ADW. That's about the weight of a newborn elephant calf.
Native to the forests of India, Pakistan, Sri Lanka and Nepal, they are close relatives of Burmese pythons, and — like Burmese pythons — their faces contain structures called "heat pits" fitted with a sensitive membrane that can detect infrared radiation emanating from warm-bodied animals up to 3.2 feet (1 m) away, according to a 2010 study in the journal Nature. This adaptation helps to guide the stealthy night-hunting reptiles towards their prey.
5. Reticulated python (32.8 feet)
Another South Asian native, the reticulated python (Malayopython reticulatus) — decorated with a pattern of repeating diamond shapes that give it its name — is widely recognized as the longest snake on Earth today. One account from 1912 claims that a captured python measured 32.8 feet (10 m) long — the length of a typical school bus — though this figure is difficult to verify.
According to the U.K.'s Natural History Museum, reticulated pythons regularly reach over 20.5 feet (6.25 m). The longest reticulated python in captivity measured 25.2 feet (7.7 m), according to Guinness World Records.
Its size, coupled with its temperamental nature, has occasionally proved fatal for humans: In one incident in 2018, a woman in Indonesia was discovered, fully clothed, in the belly of a bloated python. Yet these creatures can also be tender. Like other python species, females delicately encircle their eggs and rhythmically contract their muscles to generate heat that’s transferred to the offspring, increasing their chances of survival against the cold, according to San Diego Zoo.
4. Green anaconda (up to 33 feet)
Green anacondas (Eunectes murinus) silently slither through marshlands and streams in the Amazon, where they may live long enough to reach 30 feet (9 m) long.
Taking historic records into account, they are likely not as long as reticulated pythons. However, green anacondas are the heaviest snake species on Earth today, with some of these snakes weighing up to 550 pounds (250 kg), according to Smithsonian’s National Zoo and Conservation Biology Institute — equivalent to a baby grand piano. The hefty snakes use that huge bulk to constrict their prey of capybaras, caimans and deer.
There is no official record for the biggest green anaconda, but in 2016 construction workers in Brazil came across a snake estimated to be 33 feet (10 m) long and 880 pounds (399 kg).
Contrary to popular belief, constriction doesn’t cause death through asphyxiation alone. “The pure muscle mass of their bodies wrapped around their prey basically causes a heart attack. Essentially, it stops the rhythm and the circulation of the heart,” Campbell said. “That will immobilize prey which they can then take their time to swallow whole — normally head first.”
3. Gigantophis garstini (up to 32 feet)
While modern-day snakes can reach incredible sizes,: prehistoric snakes beat most of these present-day records. Gigantophis garstini, for example, was a hefty beast that slithered around about 40 million years ago on a body that researchers estimate was anywhere between 23 and 32 feet (7 - 10 m) long, according to a PLOS blog post.
This constrictor, discovered in Egypt in 1901, was capable of coiling its vast anatomy around prey such as early elephant ancestors — about the size of a tapir — and eating them whole. Researchers discovered that Gigantophis was related to another extinct giant species called Madtsoia whose fossils were discovered in India, suggesting that giant snakes’ reign of terror once stretched across parts of Asia too. For almost 100 years after its discovery, Gigantophis garstini held the title of the world’s largest ever snake — until even bigger specimens slithered into the picture.
2. Palaeophis colossaeus (39 feet)
Giant snakes weren’t confined to land: Earth’s prehistoric seas also contained leviathans, such as Palaeophis colossaeus. This sea serpent traversed an ancient ocean that once lay over parts of North Africa 100 million years ago. When its fossilized skeleton was discovered in the present-day Sahara desert, researchers calculated from samples subsequently collected during field trips in 1999 and 2003 that this species would have reached over 39 feet (12 m) long, according to research published in the journal Acta Palaeontologica Polonica. That makes it the lengthiest sea snake ever found — and one of the longest known snakes, period.
The snake’s head was never discovered, but from its skeleton, researchers determined that this gargantuan creature’s mouth would have been large enough to consume small whales whole.
Its descendants are diminutive by comparison. Sea snakes today rarely stretch beyond 6.5 feet (2 m).
1. Titanoboa cerrejonensis (42.7 feet)
A snake the size of a T. rex that weighs 1.25 tons (1.13 metric tons) Titanoboa cerrejonensis isn’t a fictional monster cooked up for a horror film but a real creature that once slithered through the humid forests and rivers of South America. Titanoboa was the biggest known snake to have ever existed.
Dating back 60 million years, this snake was the prehistoric grandfather of the region’s modern-day anacondas and boas. Its roughly 250 vertebrae formed a massive 42.7-foot-long (13 m) frame that it would have nourished with a diet of crocodiles and river fish. It is estimated to have weighed a whopping 2,500 pounds (1,130 kg), according to Indiana University.
Its fossilized remains were discovered in the early 2000s, studded into the rocks of the Cerrejón Formation, a geological landscape in Colombia. Since then, its record-breaking weight and length have remained unmatched — but there may still be other titans lurking out there.
“I am not closing the door to the possibility of there being yet another large, or larger, snake than Titanoboa,” Campbell said. “We just haven’t found it yet.”
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Emma Bryce is a London-based freelance journalist who writes primarily about the environment, conservation and climate change. She has written for The Guardian, Wired Magazine, TED Ed, Anthropocene, China Dialogue, and Yale e360 among others, and has masters degree in science, health, and environmental reporting from New York University. Emma has been awarded reporting grants from the European Journalism Centre, and in 2016 received an International Reporting Project fellowship to attend the COP22 climate conference in Morocco.