Boa constrictors are one of the longest snakes in the world. Before getting a boa as a pet, it’s vital that you find out how big they can grow when they reach full maturity.
Newborn boas are 14 to 22 inches in length and weigh 2 ounces. However, adult boa constrictors average around 10 feet in length and weigh over 100 pounds, with females boas being larger than male boas.
Although most Central American boas don’t grow beyond 8 feet, it is possible that they’ll grow up to 13 feet long. The longest confirmed boa constrictor was over 14 feet.
How Fast Do Boa Constrictors Grow?
Boa constrictors grow incredibly fast. Most boas reach full maturity after three years, but they continue to grow throughout their entire life.
Baby boas are often between 14 to 22 inches in length and are born into a litter of around 60 snakes.
They are among the few species of snakes that produce live births, instead of eggs that require incubation. This means a baby boa is fully formed at birth and starts feeding shortly after, allowing it to grow at a rapid pace.
If you purchased your boa from a breeder, ask them about when the snake was last fed. Feed your baby boa freshly killed small animals every 5-7 days for its optimum growth.
Never feed a boa anything wider than its girth as doing so may result in intestinal issues, stress, regurgitation, and nutritional deficiencies.
Within seven months, a baby boa can reach 3 feet or more, and weigh up to 30 pounds.
As your boa grows, expect to give it a diet rich in small mammals, such as small rats and adult mice, or other animals, such as birds or lizards – either freshly killed or frozen and thawed. At this stage, the boa will have to be fed every 10 to 14 days.
- Feeding your pet snake a live animal in its cage can be messy and even risky. Boas consume frozen or dead animals as eagerly as live ones. Stock up on fresh and frozen meat, and make sure you thaw the meat before giving it to your boa.
Use tongs while feeding your boa to avoid getting accidentally bitten. Provide ample fresh water to help it digest its food and to serve as a bathing pool during shedding.
Your boa is likely to have reached its full maturity by the end of its third year, growing to an average length of 7 feet or longer, and weighing up to 60 pounds.
Although your boa would have fully matured at this point, it will continue to grow, reaching a length of 10-13 feet or longer, and weighing over 80 pounds.
The growth of your boa is highly dependent on its diet. Overfeeding can cause a boa to grow faster, but this can be potentially detrimental to its health.
Some complications associated with overfeeding include:
- Excess shedding
- Shorter lifespan
Therefore, it’s highly recommended that you stick to feeding your boa every 10 to14 days.
A healthy boa constrictor will continue to grow throughout its entire lifespan. Slow growth or unusual behaviors may indicate that your snake is sick.
The most common illness among boa constrictors is the common cold, which may cause a boa to exhibit symptoms such as:
- Oral or nasal discharge
If you notice any of these symptoms, raising the boa’s cage temperature to 81 to 86 degrees Fahrenheit can help. A higher temperature will create a more tropical environment for your boa constrictor, helping it recover from its cold.
However, if your boa continues to show unusual behavior, or if it becomes sluggish and stops eating or shedding, it may require a dose of antibiotics to get better. If the situation gets extreme, you may even have to force feed your pet to prevent starvation.
Female vs. Male Boa Constrictors
According to an article published in the journal, Amphibia-Reptilia, female boas are much larger than male boas. The average length of a male boa in captivity is 7 to 10 feet. Female boas, on the other hand, can reach beyond 10 feet in captivity – easily growing up to 13 feet in length.
What’s the Average Weight?
Female boas are also heavier than males. On average, a male boa can weigh between 15 to 23 pounds, whereas a female boa can weigh 22 to 35 pounds. Larger specimens may even reach up to 100 pounds, or more.
Subspecies of Boa Constrictors
There are numerous boa constrictor subspecies, with the red-tailed boa constrictor and boa constrictor imperator being the most common.
Red-Tailed Boa Constrictor
On average, red-tailed boa constrictors grow up to the following lengths:
- Female Red Tailed Boa Constrictor: 7 to 10 feet
- Male Red Tailed Boa Constrictor: 6 to 8 feet
Boa Constrictor Imperator
Also known as the common boa or common northern boa, boa constrictor imperators are often smaller than red-tailed boas.
They average between 4 to 8 feet in length, but some are known to reach up to 12 feet. They weigh around 13 pounds, with females being larger than males.
How Big Can a Dwarf Boa Get?
Dwarf boas are one of the smaller boa subspecies, with males averaging between 16 to 18 inches, and females, 20 to 24 inches, when they’re fully grown.
The largest dwarf boa to be recorded was approximately 30 inches.
Why Are Boas So Big?
Boa constrictors are elongate, slender snakes, but they’re modestly sized when compared to larger snakes, such as the Burmese python or reticulated python. Boas have healthy appetites, and their size and weight are highly dependent on their locality and the availability of food.
Boa constrictors hunt birds, bats, monkeys, wild pigs and even larger mammals, such as deer. Boas are nocturnal reptiles, making them more likely to feed on bats in their natural habitat.
Boas consume and digest their food relatively quickly. They don’t have poisonous fangs but have small hooked teeth that they use while striking their prey.
They constrict their prey, stopping their blood flow. Once the animal is dead, the boa ingests its prey whole, taking six days to digest its entire meal. Because of this fast process, boas can consume copious amounts of food, allowing them to grow much larger than most snakes.
The size of a boa constrictor can also depend on its subspecies. Smaller subspecies, such as common boas typically don’t outgrow red-tailed boas. It’s also associated with its locality. For example, dwarf boas are a secretive subspecies, found under bark or on branches, in Hog Island, north of Honduras.
What is the Biggest Boa Constrictor?
Contrary to popular belief, the biggest boa constrictor was not 18 feet long, as it was later discovered to be a misidentified green anaconda.
The largest recorded non-stretched dry skin of a boa constrictor measures 14.6 feet without the head, according to a report by Frank Glaw and Michael Franzen.
Cage Size for a Boa Constrictor
Adult boa constrictors are extremely powerful and can easily escape if not kept in a securely built enclosure. While a baby boa constrictor can be housed in a glass aquarium, a larger enclosure will be required for adult boas. Boas are highly terrestrial reptiles, so floor space is more vital than the height of the enclosure.
The cage size for a boa should be 6 to 8 feet long, 2 to 3 feet tall, and 2 to 3 feet wide. Aim for a minimum floor space of about 10 square feet for an individual snake.
Include hides to help your snake feel secure. There should be a minimum of two hides, such as half logs, upside-down containers with holes cut on one side or commercially sold reptile caves. Make sure each hide is not much larger than your snake as boas prefer a more snug fit.
Related Boa Size Questions
Can I over-feed my boa to make it grow faster? When overfed, boa constrictors can become obese – just like humans can. This is highly common among keepers who continue to power feed their boas. An excessive feeding routine combined with lack of activity due to the snake being in a captive environment can cause health issues for your snake, potentially shortening its lifespan.
How large should each meal be? The small animal that you are feeding your boa constrictor should be approximately the same size as the snake’s thickest region, which is in the middle of its body. As a general guideline, the diameter of the mouse or rat should be similar to the diameter of your snake’s body. While it is okay if the rat or mouse is slightly larger than the snake, serving a much larger meal may cause your pet to regurgitate the meal.
For further information, feel free to read our in-depth boa constrictor care guide.