There are a wide variety of natural subspecies of boa constrictor found in the wild. Some have hardly been studied by scientists, let alone found and kept by snake breeders.
There are at least ten different types of boa constrictor species and subspecies, such as the red-tailed boa and boa imperator. Others are less common, such as the short-tailed boa, long-tailed boa, and black-bellied boa. Scientists are uncertain how many subspecies exist.
There’s a lot of interbreeding, and the subspecies share similar geographic ranges. We’re talking about places that are difficult for herpetologists and scientists to reach and carry out their research—the heart of the Amazon rainforest, and the slopes of the Andes. So, let’s look at the different kind of boa constrictors that are known along with some really interesting facts.
Boa Constrictor Species List
All boas are constrictors. They constrict their prey to kill it, rather than using venom.
However, when you’re talking about ‘boa constrictors,’ you’re referring to two different species in the genus Boa. One species is ‘Boa constrictor,’ which contains most of the subspecies in the list below.
The other species is ‘Boa imperator,’ which is mostly similar to the regular boa constrictor but from a different geographical range. These two species are the only two species in the Boa genus.
In the species Boa constrictor, there are at least eight subspecies that hail from different parts of South and Central America. They differ regarding size, color, and pattern.
Given that they live so close to one another, with their ranges overlapping, there’s also significant interbreeding that occurs in the wild. Breeders are careful to avoid this, only breeding like with like.
Aside from these snakes, other boas are constrictors, but which aren’t in the same species. The emerald tree boa, for example, is also in the Boa family but is in a different genus (Corallus). This isn’t considered a boa constrictor.
1) Red-Tailed Boa (Boa Constrictor Constrictor)
If somebody says they own a boa constrictor, this is probably the snake they mean. This boa is native to almost all of South America, as well as some Caribbean islands. Among snake owners, it’s known as the BCC which is an abbreviation of their scientific name.
Regarding boa constrictor characteristics, they grow to between five and nine feet on average, but can reach thirteen feet if they’re well fed. Females are larger than males, both regarding length and weight.
They range from brown to cream or gray, and have reddish-brown markings known as saddles in a pattern along their back. Their name is derived from their bright red tails, which they keep into adulthood. They can live for between 20 and 30 years if they’re well-cared for.
In the wild, they’re a nocturnal snake that likes to climb in trees, hence how many wild specimens live in the rainforest.
Facts About the Red-Tailed Boa
- When they first became popular, the majority of captive red-tailed boas were wild-caught. This gave them a reputation for being a mean and aggressive snake. Captive-bred boas, as practically all of today’s specimens are, are much more docile.
- The initial pressure on the red-tailed boa population caused them to become rarer in their natural habitat.
- Because of the sheer number of snakes in captivity here in the U.S., it’s inevitable that some are lost or abandoned. In fact, this has happened to such an extent that they’re now an invasive species in the wild in some states like Florida!
- The red-tailed boa appears across almost all of South America. At the same time, so do most of the subspecies in our list. Because the snakes all share the same range, there’s a lot of interbreeding, and confusion as to whether certain subspecies are different or are just color morphs.
2) Boa Imperator (Boa Constrictor Imperator)
Boa imperators are another common pet snake. If somebody tells you they own a boa constrictor, and it’s not a red-tailed boa, it’s probably a boa imperator. To help distinguish between the two species, these snakes are referred to as BCIs.
And yes, we said species—because some scientists think that the boa imperator is a different species to boa constrictors. These snakes live in Central America rather than South America, for example, Mexico, Nicaragua, and Colombia.
BCIs are very similar to BCCs. They have very similar markings, so much so that it’s difficult for a novice to tell them apart. To get technical, BCIs have markings that are more rounded, whereas BCCs often have a little notch in their markings, a small point on each side.
The biggest difference is that BCIs have a dark brown or dark red tail. BCIs are also a little shorter and slimmer than BCCs.
In captivity, however, BCIs are different from BCCs in terms of behavior. They’re not as gentle and docile as red-tailed boas. They’re more likely to bite if you don’t know what you’re doing with one.
Facts About the Boa Constrictor Imperator
- Scientists are not sure whether to classify the boa imperator as a separate species or not. In 1803, it was first given the scientific name ‘Boa imperator.’ In 1842, it was reclassified again as ‘Boa eques.’ In 1910 it was first termed ‘Boa constrictor imperator,’ as it was again in 1951. So, are they a separate species or just a subspecies?
- Scientifically speaking, there’s another difference between BCIs and BCCs. According to Litteratura Serpentium, BCIs have fewer dorsal and anal scales.
- Venezuelan boa imperators share a habitat with BCCs, leading to interbreeding. These snakes are like a mix of the two. Should they be classed as a separate subspecies of their own? It’s a great idea, but not one that any breeders or herpetologists are currently suggesting.
3) Short-Tailed Boa/Amaral’s Boa (Boa Constrictor Amarali)
Right, let’s move on to the less well-known subspecies. The snakes from here on out are only rarely kept as pets.
That doesn’t mean that there’s something wrong with them—they’re not hyper-aggressive or necessarily difficult to take care of—they’re not as common. Starting with Amaral’s boa, this snake was named after Brazilian zoologist Dr. Afrânio Do Amaral.
Their more common name is the short-tailed boa, because they have very short tails. This stunts their length overall, and they max out at about six feet.
Because of their short tail, they also look quite thick and stubby. This makes them quite easy to keep and handle, although they’re still not one of the more popular boa constrictor subspecies.
You can find these snakes in South America, in both Brazil and Bolivia. Some have similar coloration and to common boas, ranging from tan to medium brown, and have the same notched markings as BCCs too.
Others are a flashy silver color, leading to some people calling them ‘silverbacks.’ They’re a beautiful variation. Some breeders have managed to create red and purple color variations.
Facts About the Short-Tailed Boa
- Brazilian and Bolivian short-tailed boas are slightly different, in that the Bolivian short-tails are more similar to BCCs, whereas Brazilian short-tails are more frequently gray and brown (giving a darker appearance overall). However, it’s unclear whether these are natural variations, or the result of the snakes being from different locations.
- They’re very rare in the pet trade, especially Bolivian short-tailed boas. That’s because Bolivia blocks their export, so breeders can’t get their hands on them.
- All the Bolivian boas currently kept in the U.S. are descended from the collection of a breeder called Joe Terry. There are two lines available, Lemke and But even the Brazilian boas are only kept by a select few breeders in the U.S. and Europe.
4) Long-Tailed Boa/Tumbes Peru Boa (Boa Constrictor Longicauda)
The Peruvian long-tailed boa is a boa constrictor with a long tail from Peru. Their common name is the long-tailed boa—they’re hardly ever called the Tumbes Peru boa. Their scientific name longicauda comes directly from the Latin for ‘long tail.’
They were only discovered in 1991, by Dr. Robert Price and Paul Russo, while on an expedition in the area. The young of the specimens that they brought back are still bred and available for sale today.
There are a couple of morphs too, including albinos and anerythristic boas. In captivity, they’re very similar—they have similar needs regarding temperature and humidity, and are equally docile. They’re a more common pet than the short-tailed boa, but they’re not as common as BCIs or BCCs.
They’re a highly variable snake, ranging from dark grey and black to golden brown. Their pattern also varies, from quite similar to the BCC to much thicker, with the saddles appearing just as big as the gaps between. They aren’t very long, though, despite their name.
They reach between 5 and 6 feet on average. This is quite short for a boa, and even shorter dwarf varieties are available. There are also captive anerythristic snakes, although because the long-tailed boa isn’t very red anyway, this doesn’t make much difference to the snake’s overall appearance.
Facts About the Long-Tailed Boa
- Their color changes dramatically as they get older. They start out with their light grey background and a blurred pattern. As they approach three years old, the pattern becomes much clearer, especially around the head, and turns to black. Their background color changes from grey to yellow or golden brown.
- While the long-tailed boa is recognized as a subspecies in its own right, some people argue that it shouldn’t be. They say that it’s not significantly different from boa constrictor ortonii, another subspecies from around the same area.
5) Black-Bellied Boa (Boa Constrictor Melanogaster)
Boa constrictor melanogaster is a proposed subspecies of boa from eastern Ecuador, where the Andes meet the Amazon. In 1983, James K. Langhammer ventured out to this special area of the world in search of something interesting—and that’s exactly what he found.
As he described them, Boa constrictor melanogaster was quite different to any other recognized species or subspecies of boa constrictor. First of all, they have an entirely black belly (which is where the name ‘melanogaster’ comes from, meaning ‘black belly’).
Unlike other boas, they’re completely black underneath, from head to tail. Not only that, but they have much smaller and more numerous scales on their top side.
In some cases, the saddle pattern fuses together leaving circles, almost like islands, on their top side. In other things like size, weight and tail length, they’re similar to the BCC.
Unfortunately, nobody agreed with James’ suggestion. Some scientists pointed out that while the black belly is not seen on every boa, you can find boas with dark and almost completely black bellies elsewhere too, like Suriname and Guyana.
If these snakes aren’t a separate species—which nobody says they are—then the boa constrictor melanogaster isn’t either. Today, these snakes are seen as a color morph of the BCC. Whether or not they’re considered a separate subspecies is by-the-by, as they’re beautiful snakes.
Facts About the Black-Bellied Boa
- This snake is also called the ‘Ecuadorian boa.’ However, this is a terrible choice for a name. There are at least eight other boas found in Ecuador, including BCCs and BCIs, Lojan boas, and even boas of other species like emerald tree boas and Amazon tree boas.
- Not much is known about them. They haven’t been studied that much, because most zoologists don’t consider them a separate subspecies.
6) Dominican Clouded Boa (Boa Constrictor Nebulosa)
The Dominican clouded boa hails from the small Caribbean island of Dominica—not to be confused with the Dominican Republic. Dominica is an island, part of the Leeward Islands chain, which is north of Venezuela. Dominica is an island that’s covered in rainforest, and is home to many unique species and subspecies, among them Boa constrictor nebulosa.
This snake is a brown, occasionally gray. As they get older, their pattern becomes less distinct, the opposite of other subspecies like the long-tailed boa.
They start out a bright boa covered in dark browns, yellows and light tan colors. But as they age, their pattern fades, leaving behind the tan underneath. According to the journal Caribbean Herpetology, they feed on local bats.
In other ways, they’re similar to most boas. They get to eight feet long, and are quite sturdy too, just like BCCs. Because they’re quite different from other kinds of boa, they’re considered by some to be an entirely separate species (Boa nebulosa).
This often occurs when populations of a certain animal are isolated on an island, away from others of the same species. They will develop adaptations of their own. This provided the basis of Darwin’s theory of evolution—he noticed that birds on different islands of the Galapagos had adapted differently to habitats and prey, despite being so geographically close together.
The first ones captured and brought to the U.S. were captured by a zoologist named James D. Lazell, who donated them to the Philadelphia Zoo. They’re exceptionally rare snakes to find as a pet.
The first breeding pairs were brought back to the U.S. after an expedition by Robert A. Young and Tyler Miller, who traveled to the island to find and capture the snake that locals called ‘Tete’chein’ (meaning ‘dog’s head’ in the local variant of French). While they did bring several couples home, they seemingly abandoned their breeding project after a few years.
Facts About the Dominican Clouded Boa
- These snakes have a hereditary disease. What happens is, as they age, their vertebrae fuse together. Unfortunately, this reduces movement over time. Eventually, their back will fracture when they try and constrict a prey item. This leads to complete paralysis of any point below the fracture, just like when we break our backs. This hereditary disease may have its roots in the fact that the snake is from an isolated island population.
- In the wild, they’ve been observed nesting or sitting together. They hide in cracks in the rocks to keep warm, and presumably don’t mind sharing their space with others. Locals call these spaces ‘cavalesche tete’chein,’ meaning ‘snake tunnels.’
- Some breeders claim that their hereditary disease is a myth. Unfortunately, since there are so few in captivity, it’s difficult to say for sure.
- Others say that this snake is quite bad-tempered, more so than any other boa kept in captivity. Whether this is because hardly any captive-bred Dominican boas have ever been kept is unclear.
7) St. Lucia Boa (Boa Constrictor Orophias)
St. Lucia is an island near Dominica. The St. Lucian boa was discovered by the same James D. Lazell as discovered the Dominican boa.
In appearance, the snake is a typical boa constrictor brown and light tan. As they age, they become dark grey or even black, spreading from the tail upwards. Among boas, they have small scales, and lots more of them.
Aside from that, little is known about them. They seem to be close to extinction, because despite living on an island paradise, the locals don’t like snakes all that much. Not only that, but they’ve practically disappeared from breeders’ collections worldwide after a brief popularity in the 1990s.
Facts About the St. Lucia Boa
- Breeders with whom they were popular reported that they were an exceptionally skittish and bad-tempered snake.
- According to Lazell, you can find these boas on St. Kitts, another nearby Caribbean island.
- Lazell thought that the St. Lucia Boa should be listed as a species separate from the red-tailed boa.
8) Pearl Island Boa (Boa Constrictor Sabogae)
Our third and final island species, the Pearl Island boa is native to just a few islands near Panama. It’s by far the most perilously endangered species of boa constrictor, and it may have already been lost in the wild. These tiny islands are only a few acres across, and recent developments there related to the fishing industry—plus local wildfires—have decimated their habitat.
Fortunately, there are some captive specimens. They’re a very light tan color, and look comparatively uniform to other boas. Their saddles are quite thin, and reddish brown. Every single one of them looks hypomelanistic.
What is the smallest breed of boa? It could be this one. They only reach about five feet, which is the smallest a boa constrictor can get. You can get dwarf varieties of any species or subspecies, but in terms of size, these are the smallest. The Hog Island boa, a variant of Boa imperator, also reaches about five feet. But the Pearl Island boa is the smallest recognized subspecies.
Facts About the Pearl Island Boa
- There was a ban on exporting them until 2006. Unfortunately, local collectors take advantage of the Pearl Island boa’s rarity and pass off regular boa imperators as the rarer snake.
- Because they’re so rare, they command a big price tag compared to other boas.
9) Argentine Boa (Boa Constrictor Occidentalis)
The Argentine boa is another quite rare snake. As the name suggests, they’re from Argentina. Specifically, the north-eastern part, which is quite temperate compared to the south and the west.
Again, they’re variable in appearance. Youngsters are gray or pink, with patterns that don’t have much contrast. Older snakes are dark brown and black, with light brown accents to their pattern. They have the same notched saddles as BCCs, but have an overall spotty appearance.
In other ways, they’re quite similar to regular boas too. They range between 6 and 10 feet in length, and have quite heavy bodies. In the wild, they can survive quite low temperatures.
But as they become accustomed to living in an enclosure, they seem to lose their immunity over time. So even in terms of care, they’re similar to other boas.
Unfortunately, they’re so rare that they’re listed as an endangered species, which means that they’re illegal to capture or kill. The reason why is simple. These snakes live in the Argentine rainforest—what little of it is left.
According to the Argentina Independent, over the last century, it’s almost entirely been wiped out. The forests were cut down for timber, and their former habitat turned over to agriculture. This snake has virtually nowhere left to live.
This has put a dampener on the popularity of the Argentine boa as a pet. The fact that they’re endangered means that each snake kept by a breeder has to be scrupulously accounted for, either through photographic documentation or through a chip (like the kind other pets have).
Not only that, but it’s even illegal to sell a captive-born Argentine boa to somebody in another country. Rather than helping this snake survive despite the loss of their habitat, this made breeders much less likely to breed them, which would have been helpful.
Facts About the Argentine Boa
- They’re the only boa constrictor subspecies that are listed as endangered. That’s even though boas on small islands only have small populations too. It’s just that their habitat isn’t as under threat.
- It mostly eats viscacha, which is a kind of big chinchilla. They look like rabbits, and you can find them across Argentina and Chile.
- According to the first scientific description of the snake, made in 1873, it used to be quite common in farming country. It would stay near or even in people’s houses, killing rats and mice.
10) Lojan Boa/Orton’s Boa (Boa Constrictor Ortonii)
Orton’s boa is named after Professor James Orton, a zoologist who explored Peru and Nicaragua in 1876-77. It’s an intermediate species of sorts, similar to both BCIs and BCCs.
Known as ‘macanche’ snakes to the locals, Orton’s boa doesn’t live in rainforests like most other boas. Instead, he prefers drier and cooler environments. They live in forests, or even in rocky mountain habitats.
They vary between a slate gray or regular browns and tans, like most boas. But they do have a very red tail. Orton’s original report on the snake stated that they’re quite short and squat, but modern breeders disagree, saying the snake can reach upwards of 11, 12 or even 13 feet.
Unfortunately, like many other species on our list, this boa is endangered. Their natural forest habitat has been decimated, just like the Argentine boa’s.
Facts About Orton’s Boa
- Despite having been discovered so long ago, they’re still not a popular pet.
- Some zoologists—in the past at least—used to misname the red-tailed boa Boa constrictor ortonii.
- Their exact range is difficult to pinpoint. While they do live in Peru, their habitat is sandwiched between many other subspecies, meaning there’s lots of interbreeding.
And that’s it for recognized species and subspecies of boa constrictor. There are many more regional variants that aren’t quite considered subspecies of their own, like the Hog Island boa, Corn Island boa, Caulker’s Cay boa and more.