8 Species of Boa Constrictors

Written and verified by the biologist Cesar Paul Gonzalez Gonzalez

Written by Cesar Paul Gonzalez Gonzalez

Last update: 19 March, 2023

Boa constrictors are large, robust-bodied snakes known for their custom of suffocating their prey before eating them. Because of their wide worldwide distribution, these reptiles have modified some characteristics of their bodies to adapt to their environment. For this reason, there are a large number of species and subspecies of boa constrictors.

In the following article, you will learn about some of the most common ones, however, keep in mind that their taxonomic classification is still a matter of debate. Therefore, the scientific names listed may be different, depending on the media consulted. Even so, that doesn’t detract from their amazing characteristics – read on to learn more about them.

Characteristics of boa constrictors

In general, experts claim that in the evolution of snakes, there was a loss of limbs, until they reached appearances like those we know today.

Boas seem to have vestiges of these limbs, as if they were an intermediate step between the old and current snakes. Because of this, they’re considered the most ancestral group of these reptiles.

Boas belong to the Boidae family, and their members have the ability to capture and consume prey larger than its own head. They don’t have any venom and so they use constriction and macrostomia as a means to be able to hunt and feed.

In addition, they have an infrared detection system that helps them facilitate this process.

Most species of boas have large, wide bodies, with different types of colorations, depending on the area they inhabit. These reptiles have a great variety of physical characteristics, and so there are different discussions about their taxonomic classification. The closest relatives that they share some common features with are the pythons.

How are boas classified?

There are many controversies regarding the classification of these reptiles, so the University of Massachusetts, in conjunction with Yale, conducted research that reconsiders their taxonomy. Among the results, they found that boas and pythons, despite being very similar, are not closely related.

For this reason, boas and some similar snakes are grouped within the superfamily Booidea. Pythons have ended up being placed in a sister group to this superfamily, the Pythonidea. The previous classification held that pythons and boas must belong to the same family, because they were so long and wide, and had almost the same physical characteristics.

Boas don’t have any teeth in the premaxilla, and this, together with the morphology of their head, separates them from the python group. To get to know them better, some species of boas are listed below.

Red-tailed boa (Boa constrictor constrictor)

This is a large tropical snake, native to the Americas, perhaps the best-known of the group. It can reach 3 to 4 meters (10-13 feet) in length, weighing up to 45 kilograms (nearly 100 pounds). Its head is triangular, with small eyes and vertical pupils.

This boa has a cinnamon-gray color, with rectangular brown spots and a light belly. The name is due to the fact that on the tail, the shades can vary to reddish brown.

Boa constrictor amarali

The triangular head of this boa is adorned with a dark stripe on each side. In addition, its colors are similar to those of the red-tailed boa. The distribution of this species is wide, with pale variations of brown, brown, and red tones.

The distribution of this species is wide, as it ranges from Mexico to the north of Argentina, preferring wooded areas. Also, to defend itself, it’s capable of emitting a loud screech or even “jumping”.

Boa imperator

This subspecies is one of the smallest, although it reaches 2.5 meters (8.2 feet) in length. In fact, this reptile lacks labial pits, which eliminates its ability to detect infrared. In addition, its body is distinguished by having ring-shaped circles, plus a dark spot that starts from the eye and extends to the sides.

Boa constrictor longicaudata

This snake is an inhabitant of the jungle regions of Tumbes, Peru, which is why it is also called a coastal boa. This animal also has a dark central line and saddle-shaped spots along the body, while its color can vary from yellow to light gray. At present, its taxonomic classification is still under discussion.

Argentine boa (Boa constrictor occidentlis)

True to its name, it’s distributed mainly in Argentina and Paraguay, between the Andes and the Prana River. This subspecies usually has darker colorations with some white. This type of boa can reach a size of up to 2.5 meters.

Black-bellied boa (Boa constrictor melanogaster)

This reptile is restricted to Ecuador, near the Yaupi River, although it’s likely to cover part of the Amazon. This Ecuadorian boa is characterized by a larger tail than other subspecies, and its shades are usually pale, due to the lack of melanin in its belly.

Dominican Boa (Boa nebulosa)

The Dominican boa, as its name implies, is a species that inhabits the Dominican island in the Caribbean Sea. It’s quite similar to the constrictors, but with the difference being that its snout is more prominent and its eyes are quite convex. The coloration of this organism is darker, varying between gray and brown shades with some black spots.

San Lucia Boa (Boa orophias)

The distribution of this species of boa is restricted to the island of St. Lucia, in the Caribbean Sea, hence its name. The colors are mainly brown, with between 27 and 31 sub-rectangular, saddle-like spots and some dark spots under the jaw. In addition, its belly has pale, white or gray shades.

Although there’s a great variety of species and subspecies of boa constrictors, unfortunately most of them are at risk, due to human use of their skins for different products. One of their most important characteristics is their diversity of colors, which makes them the perfect target for fashion lovers.

Boas are territorial species, so they will only attack to eat and defend themselves. Therefore, even though they seem intimidating, the reality is that they will try to save as much energy as possible by avoiding conflict. Knowing these reptiles helps us to know how to act when faced with them.