How Fast Do Boa Constrictors Grow? - (2024)

Boa constrictors (Boa constrictor) are known by a number of names since each of the subspecies has its own name. Some subspecies only reach 6 feet, while others reach up to 12.

You may be wondering:

How fast does a bow constrictor grow?

On average, most boa constrictors take 2 to 3 years to reach sexual maturity. They typically reach full size within 6 years.

Growth Rates

When fed on a proper diet, boa constrictors grow slowly. Their exact growth rate will depend heavily on the exact subspecies. The red-tailed boa (B. c. constrictor) reaches lengths of 10 feet for adult females.

Sexual maturity tends to come with age, with most subspecies able to breed at around 4 years old in captivity. Some of the shorter subspecies have been known to take 5 years to reach sexual maturity and the majority of their final size and weight.

Snakes do keep growing through their whole lives, but the rate for adults is very slow so you will not notice much change in size yearly.

Wild Sizes

Since wild snakes have to wait for prey, they can have inconsistent growth. As ambush predators, they need to hope prey that will fit in their mouths will come by.

Since prey availability can change wildly in some localities, this means that snakes can’t rely on regular meals. Many island populations rely on nesting migratory birds for the majority of their diet.

This can leave snakes without much food for months. They can survive long periods without food, but growth and particularly weight will be stunted in favor of surviving lean times. This can mean that it may take longer for the snake to reach adult size and sexual maturity.

Males typically breed yearly once they are old enough, but females rarely breed every year. Most females wait until they have a good body condition to breed.

This is partly because breeding takes a lot of energy for female snakes. Males only invest enough energy to search out receptive females.

In Captivity

How Fast Do Boa Constrictors Grow? - (2)

Captive boa constrictors can rely on regular meals from their owner. Growth rates are typically a pretty steady upward climb so long as the snake is eating every meal offered.

The actual growth rate depends on how often the snake is fed and how large the prey item is.

Young boas fed weekly willgrowmuch more quickly than snakes fed less often. However, fast growth is typically less healthy for the snake and risks causing obesity. Snakes that are fed more frequently will also grow much larger than snakes kept on a more modest diet.

Most reports of very large boa constrictors in captivity are individuals that were power fed to encourage growth. Many of these snakes are also overweight or even obese.

Growth Rate

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Boa constrictors are well-known for outgrowing their enclosures quickly. (see my enclosure setup recommendations on my boa constrictor care sheet)

This is because many owners aren’t aware of how large their snake will end up being. Generally, a boa will grow around 18 inches during its first year.

Most boas are started in 4-foot enclosures and need to step up by the time they reach 6 feet in length. Some owners start them in smaller enclosures and are shocked when the snake outgrows it within a year.

Adults from the larger subspecies will need enclosures that are much larger. An 8-foot long female is an average for most subspecies. She will need an enclosure that is at least 8 feet by 4 feet by 4 feet high.

Most subspecies will reach this size or larger within 6 years when they are fed slowly to favor healthy growth.

You will notice that for the first 2 years of life, your boa will grow longer at a faster rate than it puts on weight. Young boas look slim compared to mature adults.

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Snakes approaching sexual maturity will grow thicker and eventually start packing on the pounds as the snake prepares to reproduce.

This can vary depending on the subspecies and how you have fed your snake. Generally, you may see this change beginning at around 4 years of age but it may take until the snake is over 5.

You will want to weigh your snake weekly throughout its life and make sure it is growing at a decent rate. Adults need to be monitored for their weight once they reach full size. You want your adult boa to stay around the same weight since they can become obese very quickly.

Normal Body Shape

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One of the challenges for monitoring a snake’s health is understanding what it should look like. By keeping it in the ideal body shape, your snake should have healthy growth throughout its life.

Boa constrictors have a square shape to the body. They should not have a very prominent spine or ribs that are easily visible. A snake that has these bones visible is very thin and likely has less muscle mass.

If you hold the snake, it should seem solid. A healthy boa that gets plenty of exercise should have good muscle mass and tone.

If your snake seems to have trouble holding onto you during handling, you may need a vet visit.

If you notice that the snake seems round or has obvious fat deposits or a thicker tail, your snake may be overweight. You may need to offer food less frequently.


Boa constrictors are considered to be slow-growing snakes, but they do get to be larger than many other common pet snakes.

Be sure you have plenty of space and be ready to upgrade your snake’s enclosure when it has reached a new length. If you have any comments or questions, please leave them below.

How Fast Do Boa Constrictors Grow? - (2024)
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