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The Top 10 Largest Snakes in the World

Larry Slawson received his master's degree from UNC Charlotte. He has a keen interest in biology and microbiology.

From the boa constrictor to the green anaconda, this article ranks the world's largest species of snake.

From the boa constrictor to the green anaconda, this article ranks the world's largest species of snake.

What Is the World's Largest and Heaviest Snake?

Throughout the world, there exists a number of snakes that are known to reach incredible lengths and weights. Although the vast majority of snakes reach an average length of only 3 to 6 feet at maturity, others have been observed in the wild that make common snakes look like babies in comparison.

From the Cuban boa to the green anaconda, this work examines the world’s largest snake species and provides direct analysis of each animal’s behavior, geographical range, as well as overall size in regard to both height and weight. It is the author’s hope that a better understanding (and appreciation) of these fascinating animals will accompany readers following their completion of this work.

Selection Criteria

In order to select (and rank) the world’s largest snakes, a number of basic criteria were necessary for the extents and purposes of this work. First and foremost, each snake described below is ranked according to its average size (length). Weight is also factored into this equation; however, it is generally considered less important than other factors presented.

Finally, because the average length of a snake can be misleading (since a number of snake species are capable of reaching massive sizes when they are within an environment free of danger, or in captivity), this work also looks at the potential size that each snake is capable of achieving under perfect conditions. This final criterion was crucial to include and proved invaluable when comparing/contrasting each of the species that followed. While it is true that these two factors leave room for potential gaps and shortcomings, the author believes them to be the best means for ranking the world’s 10 largest snakes.

The 10 Biggest Snakes in the World

  • Cuban Boa
  • Dark-Spotted Anaconda
  • Boa Constrictor
  • Yellow Anaconda
  • Amethystine Python
  • Indian Python
  • African Rock Python
  • Reticulated Python
  • Burmese Python
  • Green Anaconda
The massive Cuban boa.

The massive Cuban boa.

10. Cuban Boa

  • Average Length: 7 to 9-feet
  • Average Weight: 60-pounds
  • Geographical Range: Cuba and Surrounding Islands
  • Conservation Status: “Near Threatened” (Population in Decline)

The Cuban boa (also known as the “Cuban tree boa”) is an incredibly large snake from the Boidae family. Endemic to Cuba and its adjacent islands, this large species is found predominantly in the region’s tropical forests where prey is both abundant and easy to find. As a constrictor species, the Cuban boa actively seeks out its prey within its natural habitat, ambushing, then constricting its victims before consumption of their meal. Potential prey for this animal includes a variety of mice, rats, and larger mammals. A particular favorite of the Cuban boa, however, is the Hutia, a large rodent that is similar to a beaver in its appearance and overall size. As of October 2021, the Cuban boa is currently listed by the IUCN as a “near threatened” species, with overall population numbers declining each year.

How Large is the Cuban Boa?

The Cuban boa is a massive snake species worthy of any top-10 list. On average, the snake is capable of reaching 16-feet in length (4.87 meters), with an average body weight of approximately 60 pounds (27 kilograms). For most specimens though, average size typically lies between 7 to 9-feet. These figures, however, do not account for their maximum size, as one specimen was observed with an overall length of 19.6-feet. This makes the snake both a sizable and formidable opponent to nearly any animal on the planet, including humans. For these reasons, it is a species that should be avoided by individuals at all costs.

The infamous dark-spotted anaconda.

The infamous dark-spotted anaconda.

9. Dark-Spotted Anaconda

  • Average Length: 7 to 8-feet
  • Average Weight: Unknown
  • Geographical Range: Northeastern South America
  • Conservation Status: “Least Concern” (Population Stable)

The dark-spotted anaconda (sometimes referred to by locals as the “De Schauensee’s anaconda”) is a species of snake from the Boidae family. Endemic to northeastern South America, this non-venomous species was first discovered in the early 1900s on the island of Marajo. Although considered relatively rare, the snake is most commonly found in northern Brazil as well as French Guyana. As of 2021, the dark-spotted anaconda is currently listed by the IUCN as a species of “least concern” regarding their population numbers. However, many researchers are quick to point out that this classification is likely false given that few are seen in the wild today. With this in mind, a reevaluation of this status is likely to occur in the years ahead.

As a semi-aquatic species, the dark-spotted anaconda predominantly inhabits swampy regions at an elevation below 980-feet (300 meters). Common prey for this species includes fish, rats, mice, and larger mammals. Few (if any) predators are known to exist for the dark-spotted anaconda, with the exception of caimans and humans (who kill the snake for its luxurious skin).

How Large is the Dark-Spotted Anaconda?

To date, most dark-spotted anacondas reach an overall size of approximately 7 to 8 feet in length. However, specimens have been spotted in recent decades with an overall length of 9 to 10-feet, with a few reaching lengths in the vicinity of 14+ feet. Although this is exceptionally rare for this species, proper feeding, good health, and lack of predation in the wild (by both animals and humans) can make growing to this length a distinct possibility. In regard to overall weight, little research has been conducted in this field of study, making their average weight an uncertainty at this time. It is widely accepted, however, that the mean weight for this animal is in the vicinity of 66 pounds. As a result, the dark-spotted anaconda is an incredibly large animal worthy of recognition on this list.

Large boa constrictor on display at a local zoo.

Large boa constrictor on display at a local zoo.

8. Boa Constrictor

  • Average Length: 7 to 12-feet
  • Average Weight: 60 to 100-pounds
  • Geographical Range: Tropical Regions of South America
  • Conservation Status: “Near Threatened” (Population in Decline)

The boa constrictor (also known as the “red-tailed boa,” or “common boa”) is a species of large (non-venomous) snake from the Boidae family. Endemic to the tropical regions of South America (as well as parts of the Caribbean), the boa constrictor is an incredibly large animal that has become a staple of pet-enthusiasts and zoos. Apart from their incredible length (and heavy appearance), the animal can be easily identified by their brown or reddish “saddles” that adorn their skin, as well as their pointed snouts. Colors vary significantly with this species and are usually dependent upon the boa constrictor’s natural habitat. As of 2021, the IUCN has listed nearly all species (and subspecies) of the boa constrictor as “near threatened” with population numbers suffering a significant decline over the past few decades.

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Within their natural habitats in the wild, the boa constrictor is afforded a wide-array of animals to prey upon. These include small to medium-sized mammals and birds, along with large lizards, ocelots, bats, and frogs. To date, few (if any) natural predators exist against the boa constrictor when fully grown. During their adolescent stages, however, caiman and alligator pose the largest threat to this particular species. Birds (such as eagles and hawks) may also pose an issue for newborns.

How Large is the Boa Constrictor?

The overall size of the boa constrictor is heavily dependent upon species, locale, and environmental conditions. Nevertheless, the largest of boa constrictors typically maintain an average length of approximately 7 to 12 feet in length. Likewise, they are a relatively heavy snake, reaching 60 to 100 pounds at maturity. In regard to world records, the longest boa constrictor ever discovered was over 14.6-feet in length. For these reasons, they were an easy choice for this list as they dwarf most snake species known to currently exist worldwide.

A yellow anaconda curled up in a tree.

A yellow anaconda curled up in a tree.

7. Yellow Anaconda

  • Average Length: 10.8 to 14.4-feet
  • Average Weight: 55 to 77 Pounds
  • Geographical Range: Tropical Regions of South America
  • Conservation Status: Unknown (Insufficient Data)

The yellow anaconda (occasionally known as the “Paraguayan anaconda”) is a species of massive snake from the Boidae family. Endemic to South America, the yellow anaconda is regularly classified as one of the world’s largest and heaviest snakes. As with all boas and pythons, the animal is considered non-venomous, and relies exclusively on its ability to constrict prey. Apart from their incredible size, the yellow anaconda can be easily identified by its yellow, golden-tan, or greenish-yellow coloration, black (or dark brown) blotches, and wide head.

Within its natural habitat, the yellow anaconda primarily inhabits regions such as swamps, marshes, and covered in various brush/foliage where ample camouflage is provided via the environment. From here, the snake is known to forage for food, with wading birds serving as the animal’s primary source of food. As a opportunistic feeder, however, the yellow anaconda will consume nearly any animal that is comes across. Common dietary options include mammals (both small and large), various birds, amphibians, as well as fish and various eggs. Brocket deer, peccaries, and capybaras are also common sources of food, as well as other yellow anaconda when the occasion arises. Due to its tremendous size and weight, there are few natural predators in the wild capable of subduing the yellow anaconda, with the exception of other anaconda, caimans, and humans (which illegally hunt the snake for its valuable skin).

How Large is the Yellow Anaconda?

The yellow anaconda is an incredibly large (and massive) animal renowned for its extraordinary length. On average, a typical yellow anaconda will grow upwards of 10.8 to 14.4 feet in total length. However, a number of animals within this species have been spotted in excess of 15.1-feet. In regard to their overall weight, most specimens weigh approximately 55 to 77 pounds at maturity (approximately 25 to 35 kilograms). Nevertheless, a few yellow anaconda have been collected by researchers in excess of 121 pounds (55 kilograms). For these reasons, this species is easily one of the largest snakes in the world.

Massive amethystine python coiled around a tree branch.

Massive amethystine python coiled around a tree branch.

6. Amethystine Python

  • Average Length: 11 to 16.4-feet
  • Average Weight: 33 to 66 Pounds
  • Geographical Range: Indonesia, Papua New Guinea, and Australia
  • Conservation Status: “Least Concern” (Population Stable)

The amethystine python (sometimes referred to as the “scrub python,” or “sanca permata”) is a species of large, non-venomous snake from the Pythonidae family. Endemic to Indonesia, Papua New Guinea, and Australia, the amethystine python is an incredibly large species renowned for its size, coloration, and weight. They can be easily recognized due to their smooth dorsal scales, iridescent shine, as well as their amethyst-like coloration (hence their name). Currently, this species is listed by the IUCN as an animal of “least concern,” indicating that population numbers are stable at this time. Researchers are quick to point out, however, that illegal poaching and encroachment by human settlements could dramatically alter this figure in the years ahead.

Within their natural habitat, the amethystine python is provided with numerous prey to pick and choose from. This includes birds (both small and large), various bats, mice, rats, and the occasional possum or snake. Larger specimens in Australia have also been known to consume wallabies of various shapes and sizes. Fish may also be an option for the amethystine python, as they spend a great deal of their time near river banks and creeks to maintain proper hydration. In regard to predation in the wild, this species faces no real threat animals, with the exception of occasional crocodiles and humans.

How Large is the Amethystine Python?

The amethystine python is a massive snake in terms of its length and weight, respectively. On average, most specimens reach an astounding 11 to 16.4-feet at maturity, and weight approximately 33 to 66 pounds. To date, the largest known specimen ever found was an astonishing 27.9-feet at length, and weighted over 200+ pounds. This is considered exceptionally rare, however, and would have required perfect living conditions, regular feeding cycles, as well as positive environmental factors that most in this species do not encounter. In spite of this, the average size of 16.4-feet is an astounding feat, and easily makes the amethystine python one of the world’s largest snakes.

Indian python taking a swim.

Indian python taking a swim.

5. Indian Python

  • Average Length: 9.8 to 12-feet
  • Average Weight: Unknown
  • Geographical Range: India and Southeast Asia
  • Conservation Status: “Near Threatened” (Population in Decline)

The Indian python (sometimes referred to as the “rock python.” “black-tailed python,” “Indian rock python,” or the “Asian rock python”) is a large, non-venomous species of python from the Pythonidae family. Endemic to the tropical and subtropical areas of the Indian subcontinent (as well as Southeast Asia), the snake is commonly found in regions near rocky foothills, woodlands, swamps, marshes, and river valleys, as these areas are generally near a permanent source of water that the animal requires. Similar to the Burmese python in appearance, the Indian python can be distinguished by its yellowish-white coloration that is blotched by tan (or dark brown) spots. As of October 2021, they are currently listed by the IUCN as a “near threatened” species, as population numbers are dwindling rapidly.

From within their natural habitat, the Indian python spends much of its time in search of potential prey. Common food sources for this species include mammals (both small and large), birds, and various reptiles. Fish are also sometimes eaten (assuming the snake is capable of capturing them in time). Using constriction, prey is typically squeezed to death before being consumed whole. To date, only a handful of predators exist for the Indian python due to their tremendous size and power. These include leopards and tigers, as well as eagles and crocodiles when the snake is in its adolescent stages of development.

How Large is the Indian Python?

The Indian python is a massive species of snake, renowned for their incredible size and body weight. On average, this species grows approximately 9.8 to 12-feet in length at maturity. However, a number of species have been discovered in the wild reaching more than 15.1-feet in length. An unverified report even showed one specimen reaching 21-feet; however, researchers are unsure about the authenticity of this claim. In regard to weight, the average body mass of the Indian python is largely unknown. However, a number of specimens have been identified with weights exceeding 110 to 200 pounds in the wild. This makes the Indian python a truly massive species of snake, and worthy of inclusion within our current list.

The incredibly massive African rock python.

The incredibly massive African rock python.

4. African Rock Python

  • Average Length: 11 to 16-feet
  • Average Weight: 97 to 121 Pounds
  • Geographical Range: Sub-Saharan Africa
  • Conservation Status: “Near Threatened” (Population in Decline)

The African rock python is a species of large constrictor snake from the Pythonidae family. Endemic to sub-Saharan Africa, the African rock python is considered the largest (and heaviest) species on the continent, with two subspecies of similar proportions recognized by the scientific community. Widely feared by locals (due to its history as a maneater), the African rock python is a highly-unique species with a number of peculiar traits and characteristics. They can be easily identified in the wild by their large size, “bulky” build, dark blotches (varying between brown, olive, chestnut, or yellow), as well as their “spear-like” head. Irregular stripes are also common on this species, along with triangular markings under the eyes. They are currently listed by the IUCN as a “near threatened” species, as population numbers are in rapid decline worldwide.

As its name implies, the African rock python is predominantly in rocky and semidesert conditions within sub-Saharan Africa. However, a number of specimens are also known to inhabit forests, savannas, grasslands, and areas that are associated with permanent water sources (for hydration purposes). From here, the snake typically hunts and feeds on a variety of monkeys, warthogs, antelopes, vultures, fruit bats, and monitor lizards. Large rodents, crocodiles, goats, and even dogs or humans have also been found in the bellies of these massive animals. For these reasons, the African rock python is generally considered to be an apex predator with few (if any) natural predators in the wild.

How Large is the African Rock Python?

The African rock python is an absolutely massive species of snake, with an average length of approximately 11 to 16-feet at maturity. This range is slightly deceptive, however, as a number of specimens have been recovered by hunters reaching lengths in excess of 19.8-feet. As of October 2021, the largest recorded African rock python was an astounding 25-feet in length (although this report remains unverified by scientists). In regard to weight, the snake generally weighs in the vicinity of 97 to 121 pounds, with the largest specimen discovered weighing more than 250 pounds. For these reasons, the African rock python is easily one of the largest and most massive snakes on the planet.

A massive reticulated python.

A massive reticulated python.

3. Reticulated Python

  • Average Length: 10 to 14-feet
  • Average Weight: 100 to 170 Pounds
  • Geographical Range: Southeast Asia
  • Conservation Status: “Least Concern” (Population Stable)

The reticulated python is a species of non-venomous snake from the Pythonidae family. Endemic to Southeast Asia, the snake is widely regarded by experts to be one of the heaviest and longest species of snake in the world. Feared as a “man-eater” by many locals within its natural habitat (due to its overt aggression and behavior), the snake’s massive size makes it an incredibly dangerous species that should be avoided whenever possible. Apart from their tremendous size and weight, the reticulated python can be easily identified by its multicolored skin (matching its jungle surroundings), diamond-like scalation, as well as its rounded snout and ominous-looking eyes. As of 2021, they are currently listed by the IUCN as a species of “least concern,” implying that population numbers are largely stable worldwide at this time.

From within the jungles of Southeast Asia, the reticulated python is afforded a wide array of potential prey. Using ambush tactics, the snake commonly strikes at its prey, seizing them within its coils before constricting and consuming. Common meals include rats, mice, mouse-eared bats, and treeshaws. Larger specimens also tend to consume birds, civets, binturongs, monkeys, wild pigs, deer, and even humans (when the occasion presents itself). With the exception of juveniles, the reticulated python possesses no real predation in the wild as their massive size makes them nearly impervious to attack. Currently, their biggest enemy is humans, who actively hunt the snake for its valuable skin.

How Large is the Reticulated Python?

The reticulated python is one of the world’s three largest snakes, and reaches an average length of approximately 10 to 14-feet. As with many of the snakes on this list, however, this range is slightly misleading, as a number of specimens have been known to reach 20 to 25-feet in their overall length (with one reaching an astounding 33-feet). In fact, many reticulated pythons are so large that adult humans have even been killed by this species, with two fully-grown individuals being entirely consumed by the snake. For these reasons, humans should take great care when in the presence of this species, as they are more than capable of killing when the occasion presents itself.

In regard to weight, the reticulated python grows to an astounding 100 to 170 pounds, with females often weighing more than the males. Specimens weighing 250 to 350 pounds are not uncommon though, as perfect living conditions (especially in captivity) can result in incredible growth for this particular species. For these reasons, it is not difficult to see why the reticulated python is one of the world’s largest and heaviest snakes.

The incredibly large (and heavy) Burmese python.

The incredibly large (and heavy) Burmese python.

2. Burmese Python

  • Average Length: 13 to 14-feet
  • Average Weight: Varies Significantly (100 to 350+ Pounds)
  • Geographical Range: Southeast Asia
  • Conservation Status: “Vulnerable” (Population in Decline)

The Burmese python is a massive species of snake from the Pythonidae family of reptiles. Endemic to Southeast Asia (as its name implies), the Burmese python is regularly classified as one of the world’s largest snakes. The animal is commonly found throughout Nepal, Eastern India, Thailand, Cambodia, Laos, Vietnam, and parts of Southern China. However, they have recently been classified as an “invasive species,” as numerous snakes are now found in the Florida Everglades following an escape from a python-breeding facility, as well as abandonment by individuals using the snake as a pet. Apart from their tremendous size, they can be easily identified by onlookers due to their thick bodies, as well as their dark coloration that is spotted by brown (sometimes black) blotches across the back. They are currently listed by the IUCN as a “vulnerable” species with population numbers dwindling in the wild.

Within their natural habitat, the Burmese python is commonly found near permanent sources of water. As such, they are predominantly found near marshlands, swamps, grasslands, river valleys, and jungles. From these locations, the Burmese python is afforded a wide array of prey, including birds, pigs, goats, and various rodents (such as rice and rats). In Florida, the snake has even been known to consume entire alligators or adult deer. In regard to predation though, the Burmese python faces no true threats, with the exception of humans, alligators, and crocodiles (especially during their juvenile stage of development).

How Large is the Burmese Python?

The Burmese python is regularly cited as one of the world’s largest and heaviest species of snake. On average, the animal reaches approximately 13 to 14-feet in length, with an average weight that varies significantly (depending on their overall size). And while 16 to 17-feet tends to be the maximum size for the Burmese python in the wild, a number of specimens in captivity have been known to grow upwards of 20+ feet.

Although the Burmese python may not be as long as some of the other snakes on this list, they are considered to be one of the heaviest by far. Fully grown specimens are capable of easily growing 200 to 350 pounds. Likewise, the world record for heaviest snake is currently held by the Burmese python, with one reaching 403 pounds (verified) before its death in 1998. For these reasons, it is not difficult to see why the Burmese python is one of the world’s largest species of snake.

The green anaconda; world's largest snake.

The green anaconda; world's largest snake.

1. Green Anaconda

  • Average Length: 17.1 to 20+ Feet
  • Average Weight: 154 to 300 Pounds
  • Geographical Range: Tropical Regions of South America
  • Conservation Status: “Least Concern” (Population Stable)

The green anaconda (also known as the “giant anaconda,” “common anaconda,” or “common water boa”) is a species of non-venomous constrictor from the Boidae family of snakes. Endemic to much of South America, the green anaconda is both the heaviest and longest known species of snake in the world. It is commonly found throughout Bolivia, Colombia, Venezuela, Peru, Brazil, and the island nation of Trinidad. They can be easily identified by their long and thick bodies, eyes that sit atop their skull, as well as their olive-green coloration that is overlaid by black blotches across its back, along with orangish-yellow stripes that line its side. As of 2021, this species is currently listed by the IUCN as a species of “least concern,” indicating that current population numbers are stable.

In South America, the green anaconda is primarily found in swamps, marshlands, slow-moving streams, as well as the tropical rainforests of the Amazon and Orinoco basins. Although their movement on land is cumbersome, they are sleek, stealthy, and deadly in the water. As an apex predator, there isn’t much that the green anaconda won’t eat. Common prey includes tapirs, deer, capybaras, caiman, turtles, fish, frogs, birds, and other green anacondas. Humans remain the only viable threat to this species, as many have taken to hunting the anaconda for its lucrative skin.

How Large is the Green Anaconda?

As the world’s largest snake, it isn’t uncommon for the green anaconda to reach an average length of 17.1-feet, and nearly 154 pounds in total weight. These figures represent only averages, however, as numerous green anacondas have been discovered by individuals in excess of 20+ feet. To date, the longest known specimen was reportedly captured (and preserved) at the Instituto Butantan in Sao Paulo. The skin was approximately 32.8 feet long, and was believed to have weighed more than 300 to 400 pounds! Smaller specimens (discovered in the 1960s and 1970s) have also been discovered by researchers, with one reaching an incredible length of 24.6-feet in length, and another measuring over 25.9-feet from nose to tail. Under perfect living conditions, it remains unclear how long a green anaconda can actually grow. However, if these figures are any indication, it is believed to be substantial.

For these reasons, the green anaconda is easily the world’s largest and heaviest snake.

Works Cited

Articles/Books:

  • Belfast Zoo. “The Cuban Boa.” Accessed 11 October 2021.
  • Slawson, Larry. The Green Anaconda: Powerful, Aggressive, and Extremely Dangerous.” 2019.
  • Smithsonian’s National Zoo & Conservation Biology Institute. “Green Anaconda.” Accessed 10 October 2021.
  • University of Adelaide. Toxinology Resource Online. Accessed 10 October 2021.
  • Zoo Atlanta. “Reticulated Python.” Accessed 10 October 2021.

Images/Photographs:

  • Pixabay Commons
  • Wikimedia Commons

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Larry Slawson

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