Boa Constrictor Imperator vs. Red-Tailed Boa Constrictor

Boa constrictors are common in the tropical regions of Central and South America. If you have an interest in boas, you may have come across the terms “common boa,” “Colombian boa,” “red-tailed boa,” “BCI” and “BCC.” But what do these different names mean?

True red-tailed boas are larger, lighter in color, and have more vivid red tails than the boa constrictor imperator.

We’re going to look at boas and explain all of the different subspecies. We’ll also explore the main differences between the Boa constrictor imperator and Boa constrictor constrictor so that you can tell them apart.

What Are Boa Constrictors?

Boa constrictors are a large, non-venomous snake native to the Americas. They are famous for their method of killing prey: constricting animals until they die from restricted blood flow.

The geographical range of the boa constrictor extends from the southern parts of Mexico, in North America, down to Argentina in South America. They can be recognized by:

  • Their size. Boa constrictors are a large snake that often grows to 10 feet long, or much longer. Captive snakes tend to grow larger than wild ones, and females tend to be bigger than males. One specimen, identified in the zoological journal Spixiana, was at least 14 feet long.
  • Their habitat. Boa constrictors live exclusively in tropical areas where temperatures are high. They can reside in rainforests, woodlands, and semi-arid areas.
  • Their markings. Wild-type or “normal” boa constrictors are a cream to light brown in color, with a number of reddish-brown saddles along their bodies. These saddles become larger and rounder on the tail, giving them the appearance of having a red tail.

Boa constrictors mainly hunt small mammals and birds, and occasionally reptiles such as lizards. Though they are often feared as dangerous, man-eating snakes, they usually do not grow large enough to prey upon humans.

Boa constrictor-related incidents, according to the Humane Society, usually involve very large specimens attacking young children.

What Types of Boa Constrictor Are There?

There are 10 subspecies of the boa constrictor. Let’s take a brief look at the different subspecies and what distinguishes them from each other.

Boa Constrictor Constrictor: the “True” Red-Tailed Boa

The “original” boa constrictor, first described and defined in scientific literature, is the nominate species Boa constrictor constrictor.

They are found commonly across the northern parts of South America, including Brazil, Guyana, Suriname, Venezuela, and Peru. Though they are the archetypal boa constrictor, they are less widespread than Boa constrictor imperator.

Boa constrictor constrictors are often nicknamed “true red-tailed boas,” due to the very vivid red markings on their tails. The “true” is added in to distinguish them from common boas (Boa constrictor imperator), which are often erroneously advertised as “red-tailed boas” although they are a separate species.

Boa constrictor constrictors are elusive and sought-after in the pet trade. When they do go up for sale, they are usually at least $200-$300 each.

Boa Constrictor Imperator: the “Common Boa”

Boa constrictor imperator is also referred to as Boa imperator. This is because there is some debate between herpetologists as to whether they should be categorized as a subspecies of Boa constrictor, or a separate species altogether.

We’ll be referring to them as Boa constrictor imperator as this is how they have been taxonomized, and how they are still referred to in the pet trade. Boa constrictor imperator has many nicknames. Some of these include:

  • Common boa
  • Central American boa
  • Colombian boa
  • Northern boa
  • Island boa
  • Red-tailed boa (erroneously, as this should only be used to refer to Boa constrictor constrictor)
  • Boa constrictor

They are the most widespread subspecies of boa constrictor, occurring in most of Central America, the south of Mexico, parts of South America, and many small islands surrounding Central America (such as the Corn Islands).

They are very similar to true red-tailed boas, with some noticeable physical differences, which we will examine shortly.

Boa constrictor imperators are the most popular boa bred and kept in the pet trade. They have also been selectively bred for unique colors and patterns, known as “morphs.”

If you’re searching for boa constrictors online, Boa constrictor imperators are mainly what you will find. Pet stores often stock Boa constrictor imperators and mislabel them as red-tailed boas, either out of ignorance or to attach a higher price tag.

Normal-colored common boas can sell for as little as $75 each. Morphs are typically more expensive.

Lesser-Known Boa Constrictors

As well as the two main species of boa constrictor, there are eight species (and many subspecies) of lesser-known boa constrictor. These are confined to specific geographic locations, and not much has been scientifically documented about them. They are as follows:

  • Amaral’s boa (Boa constrictor amarali), native to Bolivia and some parts of Brazil and Paraguay.
  • Tumbes Peru boa or Peruvian long-tail boa (Boa constrictor longicauda), native only to the Tumbes region of Peru.
  • Ecuadorian black-bellied boa (Boa constrictor melanogaster), native to Ecuador.
  • Dominican clouded boa, (Boa constrictor nebulosa), native to the island of Dominica.
  • Argentine boa (Boa constrictor occidentalis), native to Argentina and Paraguay.
  • Lucia boa (Boa constrictor orophias), native only to the island of St. Lucia.
  • Orton’s boa (Boa constrictor ortonii), native to Peru and sometimes considered to be a color variant of the Tumbes Peru boa.
  • Pearl Island boa (Boa constrictor sabogae), native to the Pearl Islands off the south coast of Panama.

Not much is known about these subspecies outside their geographical area, and they are rarely bred in captivity (other than at zoological parks).

What’s The Difference Between The Boa Constrictor Imperator and the Common Boa?

The most common boa constrictor (Boa constrictor imperator) goes by many, many nicknames. Confusingly, some of those names overlap with nicknames for Boa constrictor constrictor.

The term “common boa” is often used as a nickname for both types of boa constrictor. Which species deserves the title of “common boa” comes down to a matter of individual opinion.

Some herpetologists claim that “common boa” should only refer to the nominate subspecies, Boa constrictor constrictor because it was the first species of boa constrictor to be identified and described.

Others argue that because boa constrictor imperators are more common, and have a wider geographical range, they are more deserving of the nickname “common boa.”

When you see a “common boa” listed for sale, it’s far more likely to be a boa constrictor imperator than a common boa constrictor. This is because boa constrictor imperators are more widely available and typically cost less, than common boa constrictors. However, it is far from unusual to see a common boa constrictor referred to as a common boa.

How to Tell The Difference Between The Common Boa And True Red-Tailed Boa

Whether you come across a wild boa constrictor that you want to identify, or you’re looking to get a pet boa constrictor, there are various indicators which you can watch out for to tell the two most common species apart. For ease, we’ll refer to Boa constrictor imperator as “common boa” and Boa constrictor constrictor as “true red-tailed boa.”


True red-tailed boas tend to have a much lighter background color than “normal” (wild-type) common boas. Red-tailed boas are very pale grey, off-white or cream in color. Common boas are usually tan or light brown.


True red-tailed boas generally grow to be significantly bigger than common boas. Adult red-tailed boas commonly attain 9 to 10 feet in length and have been known to reach 13 and 14 feet.

Common boas, on the other hand, usually remain 6 to 8 feet long, although they have been known to reach 12 feet in rare circumstances. Juveniles are usually similarly sized.

Dorsal Markings

Common boas and true red-tailed boas have reddish-brown saddle-shaped markings along their backs. However, these markings are not identical in shape. Common boas tend to have smoother, more rounded saddles.

The saddles of a true red-tailed boa have distinct “widow’s peaks” in the middle, making them look almost like the shape of a sideways batman symbol. They also tend to have fewer saddles.

Tail Markings

True red-tailed boas and common boas in their “natural” coloration both have much larger saddles on their tails, making their tails appear red in color.

This is why you’ll occasionally see common boas referred to as red-tailed boas, despite being a different species. However, the tails of common boas tend to be almost a mahogany brown color. True red-tailed boas have very vivid red tails that stand out against their paler background color.

Head Shape

Juvenile boa constrictors have similar head shapes, but after 1 year, the differences between the two species start to become apparent. True red-tailed boas have longer and more pointed snouts than common boas. Their necks are also thinner, making their heads seem larger by comparison.

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Lou Carter

Hi, I'm Lou. I’ve always been fascinated by snakes and reptiles. That’s why I set up – to answer every question that you could ever have about snakes as pets (and how they survive in the wild.) I hope that you find this website useful!

Cite this article:

MLA Style: Carter, Lou. "Boa Constrictor Imperator vs. Red-Tailed Boa Constrictor" Snakes For Pets, (December 15, 2020),

APA Style: Carter, L. (December 15, 2020). Boa Constrictor Imperator vs. Red-Tailed Boa Constrictor. Snakes For Pets. Retrieved December 15, 2020, from

1 thought on “Boa Constrictor Imperator vs. Red-Tailed Boa Constrictor”

  1. This was a very understandable and informational article. Have been doing research on boas for weeks now and have been so confused, this is what I needed to break it down. Thank you


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