Added 27 June 2002. Last updated 9 December 2015: updated taxonomy and added Exiliboa and Trachyboa to page.

A quick guide to



Boas have a certain notoriety, both in folk legends and in more recent lore, whether tall tales of explorers ("it was forty foot long!") or in the contemporary setting of the urban West, where they are perceived as being the pet of choice of slightly unstable keepers who allow them to escape and strangle innocent members of the public. However, disappointing as it may be to some, the reality is far more prosaic. Boas are a large family that cover snakes from the truly potentially dangerous thirty-foot giants to harmless creatures of three foot long. Although the word boa is synonymous in most people's minds with "boa constrictor", the latter is just one species of quite a large and varied group of snakes. It should also be noted that the boa constrictor, Boa constrictor, is, contrary to its reputation, a medium-sized and fairly harmless snake (although obviously care should be taken in handling). No boas are venomous, and there are fewer large boas compared with the other subfamily, the Pythons, of their family.

Pythons and boas appear superficially to be very similar, but there are certain differences. Apart from the anatomy, pythons are almost entirely an Old World family and lay eggs. Boas are generally located in the New World and all give birth to live young.

Because some boas do make good pets, while others have difficult requirements in captivity or should only be kept by people mature and experienced enough to handle them safely, I offer below a rough guide to boas that are seen for sale in the West. This is by no means an authoritative guide, simply a basic outline. If it steers a potential boa keeper towards keeping a fairly harmless Red-Tailed Boa rather than an aggressive Anaconda then it will have done its job.

Boas are almost all found in the New World, apart from the sand boas and a couple of endangered species on islands in the Indian Ocean (an area where occasionally Old and New World species meet). Of the rest, virtually all are found in the Carribean and Central- and South America.

The Classification of Boas

Boas belong to the Order Squamata (scaled reptiles), Suborder Serpentes (Snakes), Family Boidae (boas and pythons). There are several genera of boas. The traditional classification is as follows:

Subfamily Boinae:

Subfamily Erycinae:

Subfamily Bolyerinae:

Subfamily Tropidophiinae:



Excellent book covering all the boas, including the obscure species unlikely to be seen. Highly recommended.

Boas Rosy and Ground, Jerry G Walls, TFH, 1994. Walls writes well on most if not all herpetological subjects, and this is no exception: a useful and informative guide to rubber boas, rosy boas, sand boas and Pacific island ground boas, covering both natural history and captive care as well as some of the disputes over subspecies. There is a bonus chapter with sections on the Burrowing Python Calabria reinhardtii, the Neotropical Python Loxocemus bicolor and the Sunbeam Snakes, Xenopeltis sp. Recommended.

Snakes: A Complete Pet Owner's Manual, R D & P Bartlett, Barrons, 1997, New York/Hong Kong. Covers snakes in general but has a good section on the more popular and available boas.

Breeding and Keeping Snakes, Dr Dieter Schmidt (translated by William Charlton), TFH, 1995 (originally published in German under the title Schlangen [Snakes] by Urania-Verlag, Leipzig). Although a more general book inasmuch as it covers other snake families besides the boas, most books by German herpetoculturists are always worth a look. Schmidt does not cover many of the boa species other than the most common or desirable ones, and even here the reader should be aware that some of the species listed are placed under older classifications than Bartlett and Wagner's book. Nevertheless the book does have some useful sections, including a table "Compilation of Breeding Dates in Pythons", plus Genetics and Hybridisation.

Snakes of the World, Chris Mattison, Blandford, 1986/1992, London. A good book with the only reservation being that applied to Dieter Schmidt's, ie some of the taxonomy/classification is now out of date. See also Mattison's Keeping and Breeding Snakes (Blandford) which is probably more immediately useful to snake keepers.

Encyclopedia of Reptiles and Amphibians, John Breen, TFH, 1974, Neptune City, New Jersey. Now rather outdated in many details: good quick overview, but for more up-to-date information, use one of the more specific books listed above.


The Boidae (Boas and Pythons) section of the Reptile Database provided (as always) much useful information, especially regarding subspecies, distributions and the history of recent taxonomic changes.

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