Reptiles & Amphibians comparison

Anaconda vs Reticulated Python: Key Differences Explained

The short answer

They hold different records. The green anaconda is the heaviest snake, with a thick, muscular, semi-aquatic build suited to the wetlands of South America, and it gives birth to live young. The reticulated python is the longest snake, more slender for its length, native to South-East Asia, and it lays eggs. One is a boid, the other a pythonid, so their reproduction differs accordingly.

The main difference

The reticulated python is the longest snake and the green anaconda the heaviest, and the difference in build reflects an aquatic ambusher against a terrestrial and arboreal one.

These are the two snakes most often called the biggest in the world, and the answer depends entirely on whether biggest means longest or heaviest.

At a glance

Comparison of Anaconda and Reticulated Python across 6 dimensions, with an interpretation of each difference.
What differs	Anaconda	Reticulated Python	What it means
Build	Very thick and heavily muscled, with the greatest mass of any snake	Long and comparatively slender for its length	Water supports an anaconda's bulk in a way that a terrestrial snake could not manage.
Length	Large individuals commonly reported in the 5–6 m range	The longest snake species, with well-documented individuals beyond 6 m	Exceptional length claims for both species have historically been exaggerated.Reliable measurements of very large wild snakes are scarce; many published records are unverified.
Family and reproduction	Boidae — gives birth to live young	Pythonidae — lays eggs, which the female incubates	The reproductive difference follows directly from family membership.
Habitat	Swamps, slow rivers and seasonally flooded grassland in South America	Rainforest, woodland and increasingly disturbed and agricultural land in South-East Asia	Continent alone separates them; the two never meet naturally.
Lifestyle	Strongly aquatic, with eyes and nostrils set high on the head for submerged ambush	Terrestrial and partly arboreal, especially when young	The anaconda's head anatomy is a clear signal of how it hunts.
Typical prey	Fish, caiman, capybara, birds and other mammals taken at the water's edge	Mammals and birds, with prey size increasing substantially with the snake	Both are ambush predators that kill by constriction and can go long periods between meals.

Build: AnacondaVery thick and heavily muscled, with the greatest mass of any snake
Reticulated PythonLong and comparatively slender for its length
Water supports an anaconda's bulk in a way that a terrestrial snake could not manage.
Length: AnacondaLarge individuals commonly reported in the 5–6 m range
Reticulated PythonThe longest snake species, with well-documented individuals beyond 6 m
Exceptional length claims for both species have historically been exaggerated.Reliable measurements of very large wild snakes are scarce; many published records are unverified.
Family and reproduction: AnacondaBoidae — gives birth to live young
Reticulated PythonPythonidae — lays eggs, which the female incubates
The reproductive difference follows directly from family membership.
Habitat: AnacondaSwamps, slow rivers and seasonally flooded grassland in South America
Reticulated PythonRainforest, woodland and increasingly disturbed and agricultural land in South-East Asia
Continent alone separates them; the two never meet naturally.
Lifestyle: AnacondaStrongly aquatic, with eyes and nostrils set high on the head for submerged ambush
Reticulated PythonTerrestrial and partly arboreal, especially when young
The anaconda's head anatomy is a clear signal of how it hunts.
Typical prey: AnacondaFish, caiman, capybara, birds and other mammals taken at the water's edge
Reticulated PythonMammals and birds, with prey size increasing substantially with the snake
Both are ambush predators that kill by constriction and can go long periods between meals.

How they are related

The anaconda is a boid and the reticulated python a pythonid, so they belong to the two separate constrictor families and differ accordingly in reproduction. Anaconda covers several species in the genus Eunectes, of which the green anaconda is the largest, and recent work has proposed splitting the green anaconda further — a reminder that this classification is still in motion.

Telling them apart

Geography separates them absolutely: anacondas are South American, reticulated pythons South-East Asian. Build separates them where origin is unknown, since an anaconda is far thicker for its length. Pattern differs too — the reticulated python's complex net-like markings are the source of its name.

South America, thickset, in or near water: green anaconda. South-East Asia, very long, complex net-like pattern, on land or in trees: reticulated python. Longest is the python; heaviest is the anaconda — which is why both are described as the world's largest snake without either claim being wrong.

Habitat and distribution

Anacondas inhabit swamps, slow rivers, oxbows and seasonally flooded grassland, spending most of their time in or beside water where their mass is supported. Reticulated pythons occupy rainforest, woodland and river margins across South-East Asia and have adapted to plantations and settlement edges, which brings them into frequent contact with people.

Diet and ecological role

Both are ambush predators that seize prey and kill by constriction. Anacondas take fish, caiman, capybara, birds and other animals that come to the water's edge, striking from concealment beneath the surface. Reticulated pythons take mammals and birds, with large individuals capable of very large prey. Both can go months between substantial meals.

Behaviour

Anacondas are largely solitary and aquatic, and during the breeding season several males may gather around a single female in a breeding aggregation. Reticulated pythons are terrestrial and arboreal, with juveniles climbing readily. Female reticulated pythons incubate their clutch, while anacondas give birth to live young after internal development.

People and these animals

Both are hunted for skins, and the reticulated python is among the most heavily traded snakes in the world for leather. Both appear in the pet trade despite requirements that are unsuitable for most keepers. Reticulated pythons live close to people across much of their range, and both species attract persistent exaggeration in reported sizes and in accounts of encounters.

Conservation context

Neither is currently assessed as globally threatened, but both face pressure from the skin trade, habitat conversion and persecution, and regional populations vary. Trade in both is monitored under international regulation. Current status should be checked per species on the IUCN Red List, particularly given ongoing taxonomic revision of the anacondas.

What they have in common

Both are large non-venomous constrictors that ambush prey and kill by coiling.
Both can go long periods between meals after consuming large prey.
Both are hunted for skins and both appear in the international pet trade.
Both attract persistent exaggeration in reported sizes and encounter accounts.

Key differences

The reticulated python is the longest snake; the green anaconda is the heaviest.
Anacondas give birth to live young, while reticulated pythons lay and incubate eggs.
Anacondas are South American and strongly aquatic; reticulated pythons are South-East Asian and partly arboreal.
The anaconda's eyes and nostrils sit high on the head for submerged ambush.
They belong to different families — Boidae and Pythonidae.

Where people go wrong

Assuming one species is definitively the world's largest, when length and mass give different answers.
Accepting record lengths from skins, which stretch considerably during preparation.
Treating anaconda as a single species, when the name covers several.

Frequently asked questions

Which is the biggest snake in the world?

It depends on the measure, which is why both species are given the title. The reticulated python is the longest, with well-documented individuals beyond six metres. The green anaconda is by far the heaviest, with a much thicker body and greater mass at a comparable length. Neither claim is wrong; they simply answer different questions, and reliable measurements of very large wild snakes are scarce in both cases.

Why is the anaconda so much heavier for its length?

Because it lives in water, which supports its mass. A snake that spends most of its time in swamps and slow rivers is not carrying its own weight the way a terrestrial snake must, so a very thick, heavily muscled build is workable. Its eyes and nostrils are also set high on the head, allowing it to lie submerged with only those exposed while ambushing prey at the water's edge.

Do anacondas and reticulated pythons ever meet?

Not naturally. Anacondas are confined to South America and reticulated pythons to South-East Asia, on opposite sides of the world. They would only be found together in captivity. This is a useful reminder that many comparisons between large predators involve animals that have never encountered one another and never could in the wild.

Are reported sizes for these snakes reliable?

Often not. Very large snakes are difficult to measure accurately — a live animal cannot be stretched straight, and skins stretch substantially during preparation, which has inflated many historical records. Long-standing prize offers for verified specimens above certain lengths have gone unclaimed. Treat exceptional figures with caution and prefer ranges from measured animals over record claims.

Read the full profiles

Sources and methodology

How this comparison is built: FaunaHub comparisons are assembled from the sourced animal profiles behind them rather than written as standalone claims. Figures such as size, mass, and lifespan are typical ranges that vary by subspecies, population, region, sex, age, and — where relevant — whether an animal lives in the wild or under human care, so they are presented as ranges rather than fixed values. Where a common name covers a group rather than a single species, the page says so instead of implying a species-to-species match. Conservation status changes over time and should be confirmed against the current IUCN Red List. Dimensions that could not be supported from the underlying profiles are omitted rather than filled in.

What this page does not do: it does not rank the two animals, predict the outcome of a confrontation, or present either one as stronger, smarter, or better. It is not veterinary, medical, first-aid, handling, capture, hunting, or pest-control guidance. For an animal in your care, or any situation involving injury, contact a qualified veterinarian, your local wildlife authority, or emergency services.

Sources and further reading

Authoritative references used for general educational context. External links open in a new tab. These sources do not endorse FaunaHub.

UniversityAnimal Diversity Web — Eunectes murinus (green anaconda) — University of Michigan species account
ReferenceEncyclopaedia Britannica — Animals reference — Editor-reviewed encyclopedia overview entries
Wildlife referenceIUCN Red List of Threatened Species — Authoritative source for current conservation status
UniversityAnimal Diversity Web — Malayopython reticulatus (reticulated python) — University of Michigan species account
ReferenceBritannica — Reticulated python — Editor-reviewed encyclopedia entry
ReferenceThe Reptile Database — Museum-backed taxonomic database of reptile species
UniversityAnimal Diversity Web — University of Michigan Museum of Zoology — Peer-edited reference accounts for animal species

Last updated: 2026-08-04