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Captive Care of the World’s Largest Snake – Keeping the Green Anaconda

Anaconda by TruckFor a snake enthusiast such as I, not much can top the thrill of working with Green Anacondas (Eunectes murinus), in the wild and breeding them in captivity.  I consider myself very fortunate, and realize that the childhood dream I was able to live is not available to most people.  So I’m somewhat torn when asked to comment on Anacondas in private collections.  Capable of killing an adult, and far too large to be accommodated in most homes, they are obviously not suitable choices for most people.  However, Anacondas do appear in the trade, and have been successfully kept and bred.  For those with the required space, training and finances, they are, I know, hard to resist.  Today I’ll cover the key points to consider before making a decision on these fascinating, but dangerous, behemoths.

If you really are set on owning a large, usually aggressive aquatic snake, you might consider the Yellow Anaconda, Eunectes notaeus.  It is not an animal to be taken lightly, but makes a more reasonable pet than the Green Anaconda.  Actually, I suggest “cutting your teeth” on an adult Florida Green Watersnake, Nerodia floridana.  Reaching nearly 6 feet in length, this often vile-tempered beast is a handful, and may change your mind about its larger cousins!

Natural History

I’ve posted several articles on Green Anaconda natural history and field research, and so will summarize here.  Please see the articles linked below for greater detail.


The Green Anaconda may exceed 400 pounds in weight, and is the world’s heaviest snake.  It vies with the Reticulated Python for the title of longest serpent.  There is one fairly reliable record of a 33-foot-long specimen and an unverified report (eastern Columbia, 1944) of 37.5 foot individual.  In the course of tagging over 500 Anacondas, the largest I and co-workers encountered was just over 17 feet long and weighed 215 pounds.

Range and Habitat

Green Anacondas are found in Trinidad, Venezuela, Columbia, Brazil, northern Bolivia, northeastern Peru, Guyana and French Guiana.  Highly aquatic, they inhabit rivers, swamps, flooded grasslands and the fringes of cattle ranches.

Diet and Human Predation

Green Anacondas have been documented as taking young tapir, capybara, sheep, dogs, pigs, tegus, other anacondas, frogs, herons, ducks, fishes and other animals.  I have encountered Anacondas in the act of consuming a 60 pound White-tailed Deer, a 5-foot-long Spectacled Caiman and a large Side-necked Turtle.

A (happily unsuccessful!) attack on a co-worker of mine during a field study seemed to be a feeding response; other attacks were reported to me by several residents of Venezuela’s llanos region.  The only reliably documented cases of human predation by snakes have involved Reticulated, African Rock and, possibly, Burmese Pythons.  Please see the article below for more on huge snake meals.


Setting up the Terrarium

Anaconda in enclosureHatchlings measure 18-36 inches and can be accommodated in a 55 gallon aquarium equipped with 6-8 cage clips.  They will need increasingly larger quarters as they grow. Large commercial enclosures will work for a time, but after 2-3 years a homemade cage or re-designed room will be necessary.  Security is a major concern, as all large constrictors are immensely powerful and expertly locate any weaknesses in their enclosures.

The huge volume of waste products produced by even moderately-sized individuals necessitates a floor drain in most cases.

Anacondas prefer water bowls to caves as hiding spots.  Plastic plants floating on the water’s surface will provide them with security.   A hide box should also be available (I’ve found wild individuals in riverside caves).


Newspapers, butcher paper and washable terrarium liners work well for young snakes.  Larger animals are best kept in enclosures that can be scrubbed and hosed-out; wooden floors are best protected by linoleum tiles.

Do not use wood chips, as they can lodge in the mouth during feeding and cause infection-prone cuts.

Light, Heat and Humidity

Anaconda enclosures should be maintained at 78-86 F, and provided with a basking site of 95 F.  A temperature gradient is important to their health, and can only be effectively established in a large enclosure.

Bulbs located within cages must be protected by wire guards.  Heat pads or pig blankets may be located beneath the cage floor (do not place these within the cage, due to burn risk).  Red/black reptile night bulbs and ceramic heaters can be used to provide night-time heat.

Water temperature is important, as that is where your snake will spend most of its time.  Water bowls for small snakes may be located beneath a basking light; large pools will require a heater protected by a ventilated PVC tube.

A UVB light source is not necessary.


Hatchlings can take adult mice or rat pups, and soon graduate to adult rats.  Rabbits are usually the least expensive option for moderately-sized to large Anacondas.  Other options for adults include guinea pigs, ducks, chickens, fish and suckling pigs.

Captive Anacondas sometimes exhibit very distinct food preferences (often duck), and refuse all but their favored prey.  One individual under my care would eat wild-caught but not lab-raised Norway Rats, and another refused all but Muskrats.  A 10-foot-long individual can be expected to consume 100-150 pounds of food yearly.

A 60 pound deer consumed by a wild Anaconda is the largest meal I’ve witnessed.  The largest reliably documented in the literature is a 100 pound Peccary consumed by a 26’9” specimen in French Guiana.

Anacondas will tackle huge food items, but digestive disorders may result; the desire to “test” your snake’s capacity should be resisted.  I used 12-15 pound pigs and rabbits for the 16-18 foot-long individuals under my care.

A second experienced person should always be present when snakes over 6 feet in length are fed.  Food should be offered (and uneaten food removed) with a long-handled snake tongs after the snake had been maneuvered into a safe area with a snake hook.  Anacondas, no matter how long in captivity, will not distinguish between food and owner; anything moving within range will be bitten!

Vitamin/mineral supplements are not necessary.

Water bowls should be filled to a point where they will not overflow when the snake curls up within.  While the skin diseases suffered by many snakes held in damp conditions seem not to commonly affect Anacondas, dry areas should be available.

Long-Term Planning

Please consider that a 24-inch-long Green Anaconda can reach an unmanageable size very quickly.  Zoos rarely if ever accept unwanted animals, but if you find yourself with a snake that you can no longer keep, please write me for assistance.

Anaconda Head CloseupOf course, unwanted pets should never be released…the feral Burmese Python situation in Florida is a sad example of what can happen.  Many years ago an old-time animal collector told me of a litter of Anacondas that escaped from a roadside zoo near the Everglades…I trust that reports would have surfaced by now, but Anacondas are very secretive, so I’m never quite certain of what to expect…

Important Precautions

Many of the Anacondas I’ve cared for have remained quite aggressive even after decades in captivity.  Long-term pet Burmese Pythons have killed adult owners and children; Green Anacondas have the same potential.

As regards the seemingly docile individuals that are sometimes reported, it should be borne in mind that snakes are not domesticated animals, and must never be handled carelessly; otherwise calm snakes may react to odors or vibrations that people cannot sense.  Two well-experienced adults should always be on hand when specimens over 6 feet in length are fed, cleaned or moved.



Further Reading

Capturing and Tagging Anacondas in Venezuela

Green Anaconda Natural History

Giant Snake Meals (Siamese Cat to 138-pound Impala!)

Reticulated Python Natural History

Videos: Green Anacondas in their natural



  1. avatar

    Whoah. I haven’t seen a real anaconda in my entire life (good thing). Venomous or not, these giant snakes will eat you alive. I’m already satisfied after my first (and hopefully last) encounter with a water snake last 2 weeks. Atleast I know that they’re non-venomous (well, here’s my source for this info: http://www.watersnake.net/ ) and they’re too small to eat me whole!

    • avatar

      Hello Michael

      Thanks for your interest. From what I’ve read, the website you forwarded has good info; nice that they cite field studies and articles.

      Anacondas are not related to our US watersnakes, but have similar “personalities”. I’ve known a few of each that have calmed down in captivity, but overall they are quick to defend themselves…as you know, some of out southern species (Green, Diamondback) can reach over 5 feet, and so can be quite a handful. But they are very interesting..some hybridize and produce unique youngsters. Do you know the species you came across? I’d like to hear details…where, etc., if you have time.
      Please let me know if you need any further information. Good luck, and a happy and healthy holiday season to you and yours.

      Best regards, Frank Indiviglio.

  2. avatar

    Great article Frank!
    My husband and I are traveling to Peru in May this year and when I asked him what he wanted to see most there, he replied…”an anaconda”. Of course. He’s a snake nut. We won’t have enough time in our schedule to go to the northeast where I believe the anaconda are (though I imagine our chances of seeing one “in the wild” are quite rare anyway) so I’m writing to you to ask if there is anywhere where an anaconda can been seen in a respectable enclosure in Lima or Cuzco/Cusco or anywhere nearby either of those towns, we’d take a detour to check it out. I’d be most grateful for any information you can provide.

    • avatar

      Hi Candy,

      Thanks for the kind words. Unfortunately, I’m not familiar with any zoos in the region. The only reasonable chance of seeing a wild individual is in certain parts of the llannos/savanna regions during the dry season, when they are forced to use whatever water remains. In forested areas along rivers they are difficult to find, as they rarely bask and are generally quite wary. please let me know if you have other travel plans, perhaps I’ll have better info. Enjoy, hope you see lots…send me an update if you have time, best, Frank

  3. avatar

    I am writing in regards to a baby Green Anaconda we acquired from a friend who own a pet shop. They claimed he ate chicks for them, but he looks thin and in the week we have had him he has refused food. We have him in a temporary enclosure and are currently moving into a better temp enclosure with water in which he can actually swim. We have some experience with Green Anni’s……raised one from hatchling to about 5 ft when he unexpectedly died. One thing I have noticed is while most sites discuss water temp being important, they don’t discuss an actual temperature. So my question is, do you provide water deep enough for swimming and hunting? If so, what temps do you keep the water?

    • avatar


      Water should be at 78-82 F; youngsters may not come out to bask often, in which case pool should be kept at 82F. Chicks are not suitable as a sole diet; long fasts typical, and cover (floating plants etc) important; smaller ones are on menu of many predators, instinctively cautious. Vet check very impt…stool tests, etc as heavy parasite loads are typical. Death after 5 years common – parasites and other ailments can take quite some time to be fatal. Please keep cautions mentioned in article in mind…they are unsuitable for most private collections and difficult to place as they grow. Best, Frank

  4. avatar

    Is the largest and most well known . It was reported that up to 10 meters in length , but typically have an average length of 4.5 meters, even with less than a boa constrictor snake species are recorded as long as possible. But it also has more weight Is considered the heaviest snake in the world, the race is held . May weigh up to 250 kilograms and has a trunk diameter greater than 30 cm.

  5. avatar

    Hi frank, I recently became a proud owner of a female cb hatchling green anaconda and you are exactly right they have really bad attitudes. She is a very good snake and eats a medium sized rat once a week. I just have one problem, the top of her head and nose seem to be very dry. It looks like a whiteish color, I have the humidity at 60% but maybe my tank temp was to high because I have to spray my tank constantly to keep the humidity in it. Any suggestions?

    • avatar

      Hi Ryan,

      I’ve seen similar seemingly dry areas…wait until the snake sheds, that usually takes care of it. If it re-appears or spreads, then a fungal infection would be the likely cause. They need to be able to dry off…as long as there is a water bowl large enough for soaking, air humidity is not a concern; be sure to have a hot dry area available. In the habitat where I tagged then, there’s not a drop of rain for 5-6 months, air is desert-dry but shallow water is usually available. Best, Frank

  6. avatar


    I was wondering if you knew anything about the difference between anaconda and python growth rate in captivity? I’m not an expert but I’ve noticed pythons seem to grow to large size faster than anacondas. Is it related to diet, nutrition, space, etc, or is it just natural?

    • avatar

      Hello J,

      Generally related to temperature, age, python species and feeding frequency, but there are huge individual differences and also variations among populations of the same species,; Sex also plays a role, with males maturing faster but not growing nearly as large as females. Best, frank

  7. avatar

    I was wondering, if I were to feed a camera to my ‘conda to see what it looks like inside, what kind of stuff should I coat the camera with so that it doesn’t dissolve? Would plastic work?

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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