Introduction to Boas
If you’re new to the world of boa constrictors you may not be aware that there are lots of different types of “boa constrictors”. Typically what you see in a pet store or on television is referred to as a “boa”, “boa constrictor”, or “red-tailed boa”. Chances are pretty good that in all these cases the boa in question is a Boa imperator, commonly shortened to BI in the reptile world. Without getting into too much detail, this species of boa constrictor is found throughout Central and South America and is the most common type of boa in the pet trade. There are a lot of other species, sub-species and localities of boas! True “red-tail boas” belong to the sub-species Boa Constrictor Constrictor (BCC) and generally have brick red-tails and get larger than BI’s. There is a fairly good breakdown of the boa species and sub-species here – Reptifiles – if you’re interested in learning more. Also just to note, up until a few years ago the Boa imperator was actually classified as a Boa Constrictor Imperator or BCI for short. Because this change is relatively recent it’s still very common to see Boa imperators referred to as BCI’s or Boa constrictor imperators.
The Boa imperator species is found throughout Central and South America, because of this extensive range there is a lot of variety within the species. Different localities can vary in size, color, and temperament. Many of the “dwarf boas” are found on islands or specific areas in Central America, and will stay between 4-6ft depending on the locality. If getting a dwarf boa that stays a certain size is important to you, then you should make sure to go through a reputable breeder who specializes in locality boas. If you’re interested in learning more about the different boa species and localities, Vin Russo’s book, The More Complete Boa Constrictor, is probably the best breakdown. It also includes information on most of the available boa morphs.
The adult size of the boa constrictors varies based on species, locality, individual genetics, and feeding schedule. Most boa imperators in the pet trade are locality mutts, they have Colombian and various Central American localities. Unless you get your boa from a reputable breeder who specializes in specific localities, assume your boa is a locality mutt. Most BI morphs are locality mutts, females are usually 6′-8′ as adults and males are 5′-6′. Sometimes individuals will be larger than this but it’s pretty rare. Pure Colombian localities might be larger, but again, you’ll know if you have a pure Colombian because the breeder will charge a premium for this and make it very clear.
The true red tail boas, Boa constrictor constrictor’s, AKA BCC’s, are usually larger than Boa imperators. Both in length and thickness. But they do grow slower and are most sensitive to being powerfed/overfed than Boa imperators. Slow and steady is a good policy when it comes to feeding boas, especially BCC.
The term “dwarf boa” is thrown around in the industry a lot and means different things to different people. In general, most of the Central American localities are smaller than their Colombian counterparts. I own several pure El Salvador Boa imperators and all of my adults are about 4ft, including the females. Some CA localities will be larger than this, but many will stay under 6ft. There are also different species like Boa constrictor amarali and Boa imperator longicauda, that usually stay under 6ft.