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Anaconda Attacks – Notes from a Study of Wild Snakes in Venezuela

Green AnacondaHello, Frank Indiviglio here.  Green Anacondas (Eunectes murinus) and other giant constrictors inspire tall tales among those not well-acquainted with them, and respect in those who are.  African Rock and Reticulated Pythons have taken humans as prey (please see this article), and Burmese Pythons have caused fatalities, but information concerning Green Anaconda attacks is sketchy.  Their aquatic lifestyle and tendency to inhabit sparsely-populated areas renders it difficult to discern fact from fiction.  Today I’d like to provide some personal observations drawn from my time working with Anacondas in the field.

Tagging Wild Anacondas – a Herper’s Dream Job

In the mid 1990’s, while working for the Bronx Zoo, I had the good fortune of participating in a long-term field study of Green Anacondas in Venezuela – the first and only one of its kind.  Over 900 specimens were captured, and a treasure-trove of new facts was documented.

Attempted Human Predation?

Two incidents that occurred during the study indicated that Green Anacondas may view humans as a potential meal.  A co-worker of mine was grabbed near the knee by a large female while walking in shallow, densely-vegetated water.  The snake bit her pants, which tore, and then struck again, higher this time.  Fortunately, the strike did not connect, and my co-worked escaped unharmed.

The researcher involved was well-experienced in finding Anacondas by shuffling about in likely areas, and certainly would have noticed a large snake had she stepped on it. Therefore, I doubt that the snake’s strike was in response to being disturbed.  In any event, all other snakes uncovered in this manner tried to escape.  I believe that the attack was predatory in nature.

My notes indicate that, at a later date, the same snake (all were marked) rose to the surface and, for want of a better word, “watched” researchers who were poking about nearby.  Perhaps she was an especially bold individual…

In the second incident, an Anaconda’s head appeared behind a researcher who was walking among floating aquatic vegetation.  The snake reared up and followed the man for several feet while tongue-flicking.  A co-worker noticed and grabbed the snake as it struck, causing the animal to miss her (males, the smaller sex, would be unlikely to tackle such large prey) intended target.  Due to the “stalking” aspect of this incident, we can rule out defense as a motive.

Are People on the Anaconda’s Menu?

Anaconda attacks have been researched in several books and articles (the events above are recorded in Rivas, J. A. 1999. Life history of the green anaconda. Unpublished Ph.D. dissertation, University of Tennessee).

Several incidents described in Tales of Giant Snakes (Murphy & Henderson, Krieger: 1997) parallel those above, and may involve attempted human predation (the photo on the cover of this book, not well-chosen in my opinion but quite dramatic, was taken during the study in which I assisted).

In his wonderful book Snakes, the Evolution of Mystery in Nature (U. of CA Press: 1997) Harry Greene does not cite any incidents of Anacondas preying upon people.

Clifford Pope’s classic, The Giant Snakes (Alfred Knopf, NY: 1965) recounts several interesting Anaconda encounters, including one wherein a woman battled a 19-footer in order to save a duck, but concludes that all involved defensive actions.  Incidentally, Mike Tsalkis is mentioned in The Giant Snakes – older herp enthusiasts will remember the dramatic photos of him wrestling an Anaconda in the 1960’s Life Nature Series book The Land and Wildlife of South America – it’s as clear in my mind today as when I first saw it!

Defensive Attacks

Most snakes will attempt to bite when attacked, and Green Anacondas are particularly vigorous in this regard.  I was on hand when the study’s largest snake was found.  We stumbled (literally!) upon the 17-foot-long, 215-pounder in a shallow pool that also held another individual nearly as large.

As I groped about below the water, her massive head reared up next to my face.  I deflected the strike and grabbed her neck, but was bitten in the process.  The tooth that lodged in my wrist as a result remains there today (it is close to a nerve, and not worth removing); other than a bad infection (in me, not the snake!), the “souvenir” has caused no problems.

A large female that we cornered in a riverside hollow seemed to access her options for a time and then charged.  She may have come at us open-mouthed, but all happened so quickly that it was hard to tell.  She made it through our “line”, but we tracked her progress in the river and captured her shortly thereafter.

Green Anaconda Diets

Captive Anacondas are notorious for being “picky” feeders.  Various individuals under my care have refused all but muskrats, ducks or wild-caught Norway Rats.

As a species, however, they take an amazingly range of prey.   Meals I’ve observed included, among other animals, a 60 pound deer, Spectacled Caimans, a large side-necked turtle, a Red-Footed Tortoise, wading birds, fish and other Anacondas.  Please watch for my future article on this topic.

The World’s Largest Snake

The extinct, Anaconda-like Titanoboa may have reached 43 feet in length and weighed in excess of a ton! The Smithsonian Channel will soon air a special on this incredible beast. Please see this article and video to learn more.

Please check out my posts on Twitter and Facebook.  Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable.  I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.

Please also post your questions and comments below…I’ll be sure to respond quickly. 


Thanks, until next time, 

Frank Indiviglio


Further Reading

Anaconda Taxonomy (4 species)


Anaconda Expert Wades Barefoot


Captive Care of the Green Anaconda


Hunting Anacondas in Venezuela


Giant Snake Meals

Green Anaconda image referenced from wikipedia and originally posted by Stephen G. Johnson


  1. avatar

    Wow great post Frank, I absolutely love this site and I’m grateful for your generous sharing of knowledge – yay you mate!

    Awesome post.

  2. avatar

    JUST WOW FRANK! awsome post i’ve been watching alot of documenterys lately where they do the same thing looking for big anaconda most are herpetologist I thout that would be a great job/experience and i hope one day i get the chance to work as a herpetologist and study the spectral camien. There isnt much edvidence of the anacondas / big snakes eating people but it does happen and im suprised myself it doesnt happen more if you ask me human is alot easyer of a prey to digest / take down then a alligator which they are now eating in florda or even the = of a capybara easily wighing 100pounds is one of there favorite meals and they take deer with horns/caraboo in documenterys i’ve watched youd thing the horns would damage these large snakes huh? anyways i found it intresting that the female was picked out both times seems like they are just choseing natural prey to me!

    P.S a news acrticle just came out yesterday on yahoo that a anaconda exscaped its enclosure (in a petstore) and crawled threw the air vent and strangled both of her kids 5 and 7 tragic story if true but it just seems to me that the snakes know what prey they can and cant take and act instictively.

    • avatar

      Hi Cody,

      Thanks..I was very lucky to have been able to study them in Venezuela; let me know if you need advice on careers, etc…not an easy path, but worthwhile. You may see Jesus Rivas or Maria Munoz on some of those shows…they conceived the project, and remain good friends. Another friend works with black caiman in Guyana (is that the species you meant?).

      Predation likely most common in southern Africa…Rock Pythons adapted to extra large prey items; I’ve read of several instances over the years in Herpetologica, Herpetological Review, etc. CVaptive Burmese kill people every so often (was a python not involved in the recent story you mentioned?)…I’ve dealt with one case personally. This story amazed me…there’s so much nonsense on the net, but one of the researchers involved in the study was Harry Greene, and it was published in a peer reviewed journal – in any case, his work is unimpeachable.

      Best, Frank

  3. avatar

    Thanks frank i do belive the ones i watched had them in it i expecily rember Jesus Rivas and the other one i watched had a woman who was jumping on a 20 foot green andaconda I was suprised. and knew i had to find a lady like that haha

    I did mean black caiman /but any of the croc/alligator family would be a fun rescearch!

    I often get my Large snake species mixed up this is sompthing i have to work on.

    I will ask for carer edvice tomarrow as it is getting relly late when you are and here for i have been haveing some confusion on where to start and im 18 reddy to go to collage! where can i message you for your carer advice?

    thanks frank!

  4. avatar

    Much agreed frank!…

    I guess i will post here.

    1. If i were to be a herpetologist Should i start my career In collage schooling If so what classes should i take at the grays harbor collage they just updated their wildlife programs my dad did streams and their ph / silt all kinds of stuff there..

    2. Would working at a petstore if possible boost my vallue? Unforitily their is only one petstore that actuly sells pets around here and its petco which i don’t get along with bc everyone who worked their told my girl friend what ever she needed to heair to go home with a bearded dragon and leo and never gave her any info..

    3. Is being a speclised veterinarian for reptiles and amphibians / wildlife animal rehabilitator a bonus to being a herpetologist or are these verry long fields in their own and would take away from my time as a herpetologist and what ever happens on my way their.

    I feel im forgetting stuff But if it comes back to me ill let you know.

    Thanks so much for the info frank.

    It means alot to me and now my parents have supported my studies much more.

    • avatar

      Hi Cody,

      Nothing beats having a family that encourages your interests…I was very fortunate in that regard.

      A general background in biology, zoology, wildlife studies etc. is all applicable. Several colleges are known for their herpetology programs, but I believe specialized courses would likely be taken in the final 2 years. I’m not up on curriculum changes, etc., but you should be able to find online..if not, let me know and I’ll ask some contacts.

      A museum, nature center, zoo-based volunteer program etc would be much better. Zoo generally do not think highly of pet store experience, even for beginning zookeeper jobs (I started in the pet field, but was fortunate that in those years, in NYC, there were 2 major pet importers that supplied zoos, etc). Wildlife rehab licenses, membership in local or national herp societies, museums, all very useful. Experience may help you, but probably not your CV. Try contacting local teachers, professors…many have their own research interests, and value volunteer assistance. earth watch type experiences can be useful also, although expensive.

      Some zoo directors, etc are vets (a friend, Dr Kevin Wright, well known in reptile med, is a good example) and larger zoos have field research programs that utilize vets. Several of the Bronx Zoo’s vets spend much time in the field, and in research; work within zoos as a vet can also be exciting, and you always have a way of earning additional income in private sector..

      I know several medical doctors (human) as well who have intense interests in herps…2 became very successful, financially, and donate to zoo projects…in return, they get to participate in research programs, etc. One has app. 2,500 turtles in his private collection – un-named species, etc!!! Important to think of finances well ahead of time, as typical zoo salaries are low, even for advanced professionals (compared to work outside the zoo/museum world).

      After all is said and done, i still credit all to my parents and grandparents…you seem like a responsible man, so I’m guessing you’ll feel the same…

      Following is a response I’ve sent to folks seeking general career info (zookeeping, herpetology); please let me know your thoughts/questions, and send in any questions as they arise. Thanks for posting here, very useful to others; helps me with time mgt also.

      You’ll need a 4 year degree for an entry level animal keeping job at larger, well known zoos; a masters to move into other areas, and a pHD for higher level curatorial, museum research jobs etc. Field work was a favorite of mine, but I did it as an aside to my work for the zoo…pure fieldwork is usually from “grant to grant”, and not as easy route to go, but many do and would not trade . Bx Zoo and some others employ full time field people, geneally pHd’s or grad students. While it may be easier to rise in ranks in smaller zoos, larger well-funded orgs offer more options in most cases. Zoo keeping is wonderful at many zoos, and many get hooked on it early on. However, salaries are abysmally low, given the education required, esp if you live in/near a large city, some folks work as keepers, take more schooling while working (I did this re my masters) and then seek other jobs. Some zoos have a policy against promoting keepers to higher levels (at least above supervisor) but rarely admit this, so you’ll need to find that sort of info out from staff members, etc. But a keeper position in , ie the Bx Zoo, has often been a stepping stone to curatorial spots elsewhere.

      Volunteering, esp for biology professors but also zoos, nature centers etc is invaluable; also, working with specific professors as you go on is very impt..the connections they provide are vital. I was shy, always juggling several jobs, and missed this aspect…makes the road more difficult if you try to go it on your own.

      Some go into full time teaching at universities, locking in a paycheck etc, consulting on the side and doing field research, perhaps supported by the college, in summer.

      For further career info, please see the CNAH website and the ASIH website http://www.asih.org/jobs …great way to stay up on news, see what sort of institutions, research ops etc. are out there. This article of mine (there are 2 Parts) has some additional info as well. Also the AZA job list will give you an idea of the types of positions available at zoos, sometimes includes field research, museum work. More career info from CNAH: http://www.cnah.org/default.aspx, http://www.cnah.org/default.aspx .

      SSAR: Careers in Herpetology http://www.ssarherps.org/pages/careers.php

      Some related fields that may offer much more in the way of salary, opportunity include bio-medical research (medicine from frog skin, etc), agricultural pest research, conservation genetics, etc.

      The major herp journals are a great way to stay up on serious research, but are rather costly (libraries may be able to get via inter-library loan..librarians are amazing people, and very much under-utilized); please see this article for some examples. This rather new journal is available free on line, and seems to be very well done. good to get into the habit of reading professional articles, will go a long way in helping you focus, and will distinguish you from the many (very many!) people with similar interests but less enthusiasm, discipline.

      There’s quite a bit more to this…please don’t hesitate to be in touch soon or in time, I’d love to be of some use if possible.

  5. avatar

    Thanks verry much frank means lot too me!

    I’m takeing the rest of the day to right down all important info in my notes allso i booked marked all websites and will be doing some deep studying there.

    And you are right nothing is beter then family who supports you.
    I know that theres gona be alota hard times and ill probly have to move from the harbor in the future for studies and special classes (thank goodness)

    My grandparents are verry wealthy… ill put it that way they have been buisness people all there life.

    They verry much support my intrests and whereever it make take me. and i know i can count on them if theres hard times!

    i have recetly applyed for many normal jobs, That i can do while i go to school for money on the side like you said. the reason why i havent started schooling yet is i was prity confused on where to start and then go from there so thanks so much for the info frank after i take this all in i will definitly have more to ask.

    • avatar

      Glad it was useful Cody.

      Most of the people I know, who went far in this field, had significant financial help..otherwise it is just too expensive to get an education, and the payback, in terms of salary, is low..hard to catch up. With some support, you’ll be able to focus on school, also to volunteer, work for professors, go on various trips…all take time and money, but are very helpful to your future. The people who love you will be happy if you are happy in your career, and you’ll be better at a career that interests you.

      You’re thinking of all the right things, glad to hear it. Pl keep me posted, best, Frank

  6. avatar

    I wanted to make a special thanks for the herpetological conservation & biology article has some verry verry in depth stuff i just wouldn’t be able to find on google myself. and i like to know anything and theres expecily good info on indepth history of the animal you’re reading about.

    • avatar

      My pleasure, Cody. You can also use google scholar search to find professional journal articles. In most cases, you’ll get an abstract only (sometimes full article), but if it interests you then you can request that issue from a library. You;ll find info that is not covered in the sources that everyone else uses, and it’s good practice for future; also a great way seeing what type f research herpetologists are involved in. Enjoy, Frank

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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