Added 17 January 2010.

Giant Snakes

Heroes, Villains or Misunderstood?

In recent years there has been a great deal of interest, both among herpetoculturists and the public at large, in very large, or giant, snakes. Part of this is genuine fascination for some of the longest creatures alive today, but part is also due to fascination with the spectacular and, less laudably, a desire for showmanship, one-upmanship or sheer ignorance. While I respect the knowledge of some of TV's reptile-oriented presenters, films of people unnecessarily wrestling large snakes to the ground or muttering about the danger to human life do nothing to grant people a clearer understanding and fuel the excitement of some while increasing the instinct loathing towards snakes of others. This article is a short piece written to clarify what we mean by "giant snakes", to get a sense of proportion towards them and also to point out why for many people they are less than ideal pets.

What is a giant snake?

For the purposes of this article, a giant snake is classified as any snake above 20ft in length. Of the three thousand or more species of snake on this planet, the vast majority fall way below this minimum threshold, including the boa constrictor which in fact is only a medium-sized to large snake. In fact only five species fall into this category:

Species name Common name Maximum size
Python natalensis Southern African Rock Python Sizes of over 20ft claimed
Python sebae Central African Rock Python Sizes of over 20ft claimed
Python molurus vittatus Burmese Python 25ft
Python reticulatus Reticulated Python 33ft
Eunectes murinus Green Anaconda 30ft

As can be seen from the above, the two African Rock Pythons are not even a certain inclusion into this category. However, the fact that they are recorded as having killed humans (see below) leads me to include them.

Length itself is not necessarily a guarantee of strength: some snakes can be very long but also rather slender, making them more the equivalent of a long rope than a steel hawser. However, this does not apply to giant snakes, all of which by necessity have a certain minimum diameter in order to support such lengths as well as the necessary muscle to move their bodies. It should also be remembered that reptiles carry proportionately less fat than mammals, so most of a snake's body is indeed muscle rather than adipose tissue.

From a scientific point of view, there are advantages of giantism. Just as lions and tigers can take advantage of the larger mammalian prey animals in their territories, so can giant snakes. If anything the giant snake has an advantage over its feline relatives, since being cold-blooded it can often take a single large prey item occasionally, whereas the big cats need to feed on a fairly regular basis to keep their warm-bloodied metabolisms running. Contrary to what one might expect, giant snakes do not need to eat more often than smaller snakes: fasts of a year or more are not uncommon. The major disadvantage of giantism, of course, is that if the evolutionary tables are turned then the giant snake becomes an easy target for its enemies. This has become the case for the giant snakes as for the big cats, as man has developed firearms to defend himself and his property, and to hunt animals for their skins and meat.

Are giant snakes dangerous?

At the outset of this discussion, one thing should be made absolutely clear: despite pictures on the Internet and other tall tales, there is no recorded case of an adult human being ever being devoured by a snake. Despite the huge maw of a giant snake, it seems that the adult frame is simply too wide below the neck for the shoulders to pass the snake's jaws.

Nevertheless the danger to humans does exist. There are two recorded cases of young humans having been taken by the Central African Rock Python, and other cases may exist for the other giants. The danger would seem to be twofold: (a) a perception by the snake of a human being as a threat, and (b) an opportunistic chance for a hungry snake to take fairly vulnerable prey, or (c) a human being mistaken for something else. The second case would probably only apply to children. This leaves (a) and (c) as the most probable dangers.

Reticulated Pythons and Green Anacondas have a reputation for being fairly aggressive. This does not mean that they deliberately seek out conflict, but rather that their response to a perceived danger or unwanted intrusion is one of fight rather than flight. The attack may take the form of painful bites delivered by the recurved teeth, or in its potentially fatal form, an actual constricting attack against a human. Should the human be alone when the snake attacks, if the snake is of a size over 25ft then I would suggest that the snake is most likely able to kill the human should it wish to press home its attack to the limit - and once snakes start constricting, they tend to follow through until they are convinced that the object of the attack is dead. The human in such encounters is usually further disadvantaged by the environment, either forest (in which case the encounter may be sudden and at very close range, and if not on a path then the human is forced to move clumsily through the undergrowth) or water (in which case the movements of the human may be impeded if there is sufficient depth).

It should also be noted that it is a myth that giant snakes need to anchor themselves to an object such as a tree or rock to successfully constrict their victims. They do not. Nor does a giant snake actually need to crush its victim, as some folk legends or popular misunderstandings suggest - the snake simply tightens its coils until the victim's breathing or heart give out. The pressure is nevertheless fairly considerable.

Giant Snakes in Captivity

Since the 1990s there have unfortunately been some publicized incidents where a giant snake kept in private captivity has injured, attempted to kill or killed a human member of a household. In one incident a free-roaming boid fatally constricted a child: in other, a young keeper was killed although he kept the python in a cage.

What sadly seems to have been common to most of the cases I have read of over the years is that certain safety precautions were ignored or not known. Rather than ascribing malevolence to these reptiles, it is more worthwhile to consider the following:

The above points suggest the following precautions: This will inevitably raise the question in some people's minds as to whether giant snakes should be kept at all in private hands. My answer would be the same as to whether large, potentially fierce dogs should be kept: it depends on the owner's maturity, means and circumstances. Far more people, especially children, have been hurt or killed by fierce dogs: and again, often the attacks could have been prevented by better control or supervision of the dog. I believe giant snakes are valid objects of interest for those interested in herpetology, but the potential owner of a large boid must ask themselves whether they have the time, money, space and dedication to keep the snake happy as well as protecting themselves (in contrast with dog attacks, it is normally the snake keeper who suffers when things go wrong). At the very least the size of the enclosure for a giant snake must be taken into consideration, and the need for a large body of water in the case of the Green Anaconda. Finally, it should be remembered that few zoos or other private keepers these days are likely to be willing to take on a giant snake should you find yourself unwilling or unable to maintain it.


Most introductory books on snakes will (rightly) not recommend giant snakes for beginners and may warn against them. There are however few sources in English on the care of very large boids.

The General Care and Maintenance of Burmese Pythons, Philippe deVosjoli, Herpetocultural Library Series 200, Advanced Vivarium Systems, 1991. DeVosjoli's book gives guidelines suggested by the American Federation of Herpetoculturists for the responsible keeping of large (and giant) snakes near the beginning of the book, and the author also briefly covers the other giant pythons.

Burmese Pythons plus Reticulated Pythons and Related Species, Philippe deVosjoli and Roger Klingenberg, Herpetocultural Library 2005. I have not read this manual but it appears to be an update of the previous book.

Pythons: A Complete Pet Owner's Manual, Patricia Bartlett and Ernie Wagner, Barrons, 1997, New York/Hong Kong. Another good English language source. Their companion book in the same series, Snakes, also dedicates a chapter to boas and pythons and contains cautionary comments to those thinking of acquiring a giant snake.

Boas: A Complete Pet Owner's Manual, Doug Wagner, Barrons, 1996, New York/Hong Kong. Companion book to the above: includes brief section on anacondas.

I have not read the following, but they may be of interest to those who wish to know more about giant snakes:

Tales of Giant Snakes - A Historical Natural History of Anacondas and Pythons, J C Murphy and R W Henderson, Malabar 1997.

Anacondas, H Bisplinghof and H Bellosa, Professional Breeders Series, Frankfurt am Main 2007.

The same title is also available in Dutch, as Praktijkraadgever Anakonda's

German language sources often include English translations of their titles. However I have found the following titles in German only, which is a shame as they probably deserve a wider audience, although I have not read any of the following:


There is, or was, a Giant Snake Society in the UK. A Google search may turn up contact details for it. Similarly, entering the word Riesenschlangen in a search engine will bring up German sites dealing with boids, some of which have an English language option, although it should be noted that the German word generally covers all boids, not just the giants listed above.

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