Boa constrictors are one of the most popular pet snakes and are known for their large size and beautiful patterns. Though their are many types of boa constrictors of various size, we are going to focus on the common boa or red tailed boa. After all, it is important to understand how big boa constrictors can get before purchasing one.
Red-tailed boas or common boas typically grow up to about 2-3 meters in length, with females usually growing larger than males. Their average weight normally falls between 60-100 lbs. Still, sizes may vary widely, as their environment and feeding routine directly influence their size.
When most people imagine boa constrictors, they envision a massive serpent that they may not be able to control and handle past maturity. Luckily, this snake’s size is largely exaggerated.
That said, these snakes are not necessarily small either. To determine whether this is the right species for you (and provide it with the best possible care), you’ll need a realistic idea of what to expect in their growth. Check out the guide below to learn more.
How Big Boa Constrictors Get In Captivity?
Red-tailed boas, more formally known by their scientific name Boa constrictor, are beautiful, formidable animals. Part of what draws so many people to this breathtaking creature is its size.
Admittedly though, the boa’s size has been slightly exaggerated by enthusiasts around the world. This snake is relatively modestly sized when compared to other large species like reticulated pythons and anacondas.
Still, its size is nothing to sneeze at: The maximum length ever recorded for a red-tailed boa just exceeded four meters (more than 13 feet) – larger than two fully grown men! However, not all boas get this large.
Normally, you can expect a red-tailed boa to grow between 2-3 meters (6.5-10 feet) in length, with exceptions and variations known as “island forms.”
Island form red-tailed boas tend to be smaller than others, often falling below two meters long (over 6.5 feet). Scientists have recorded wild populations on Central American islands where these dwarf varieties live, noting that different physical features and growth patterns characterize them.
The unique ecological pressures they experience on these islands versus the mainland seem to play a direct role in the size differences between these snakes and the average boa. (Source: Oxford Academic)
Boa Constrictor Size: Female Boas Get Larger Than Males
Female boa constrictors are usually larger than males in both mainland and island boa populations. Though this is uncommon with most animal species, it is very common with snakes.
Female boa constrictors and pythons are grow to larger sizes than males. However, due to how body size may vary widely between individual snakes, there is no clear data on each sex’s precise lengths.
It is known that males will typically only be larger than females in the tail, specifically. Proportionally, male boa’s tails are longer than females’ tails because of the extra space taken up by the hemipenes (reproductive organs).
How Much Do Boa Constrictors Weigh?
When considering how much boa constrictors can weigh, it is critical to remember just how much of a role body length and diet can influence this physical feature. While one snake may be longer than another, this does not necessarily guarantee that it will be heavier.
Just like human beings, some boa constrictors are naturally thicker than others. You cannot exactly base your snake’s weight expectations on their projected length, although the two can coincide. Estimates for boa constrictors’ weight vary widely, with experts reporting averages from 60-100lbs.
How Fast Do Boa Constrictors Grow?
Numerous environmental, dietary, and biological factors influence the rate at which a red-tailed boa will grow:
- Females boas in good health can grow up to 6-7 ft (1.8-2+ m) in the first three years of life.
- Males, on the other hand, will typically reach 4-6 ft (about 1-1.8 m) within the same period.
Keep in mind that, as your boa ages, it will not stop growing; instead, its growth rate will slow. Given that these snakes can live between 25-40 years in captivity, you’ll want to pay close attention over the years to ensure that your boa is always comfortable in its enclosure.
As you can infer, younger boas will grow much faster than their older counterparts. So, you must be ready to provide your snake with the optimal enclosure space to accommodate their rapid development.
Boa Constrictor Birth Size and Growth Speed
At birth, red-tailed boas should measure between 12-18 inches long, but they max out their enclosure before you know if you’re not careful.
Many owners and experts have reported that younger specimens can grow quite rapidly when on a wide range of diets, often growing into an adequately-sized enclosure within three years.
(The best diet to support a healthy growth rate for your red-tailed boa includes rodents, chickens, and rabbits.) Remember that periodic hormonal changes can influence the rate at which your red-tailed boa grows as well.
For example, your snake will reach sexual maturity once it grows to approximately 1.5 meters (5 ft) long. According to reptile researchers, “ectotherms [‘cold-blooded’ animals]… often exhibit extensive growth following attainment of sexual maturity.”
This is largely due to the influence of hormones circulating throughout the body during this life stage.
Factors that May Impact Boa Constrictor Size
Aside from hormonal changes, researchers have also confirmed that temperature can play quite a large role in the rate at which your boa might grow. Since reptiles are ectothermic – meaning they use the external environment to regulate their internal temperature – the warmth or coolness of their enclosure can either support or hinder a healthy growth rate.
Warmer temperatures allow snakes to break down and absorb nutrients more efficiently than they would in cooler ones. As the body takes in the digested materials, it can produce enough energy to fuel the development of bodily tissues, allowing the body to mature physically.
The temperature of your snake’s enclosure can also extend or shorten specific growing periods, contributing to either growth spurts or lulls in their development.
It’s important to understand that external environmental factors such as temperature and diet can have more of an influence on your red-tailed boa constrictor’s growth rate than their biology.
For this reason, scientists have repeatedly observed dramatically different growth rates and adult body sizes in several snake species, the boa included.
How Feeding Can Influence Your Boas Size
One example of how feeding patterns can interact with bodily growth was illustrated by a research team’s observations of a free-range python population. After 13 years of studying the wild snakes, the scientists determined that even siblings’ growth rates differed drastically due to the excessive weight of environmental over genetic elements.
Prey availability was a central feature of the varying growth rates, so snakes that hatched in years where rates were in abundance grew much faster than those that did not.
With this in mind, if you would like for your snake to grow consistently and reach a formidable size and length, regular, substantial feedings are necessary.
Another study confirmed the role of diet in snakes’ developmental patterns when comparing two different feeding regimens. They provided one group of snakes a weekly diet amounting to 10% of their body mass, and the second group, a biweekly feeding that equated to 20% of their body mass.
Although both groups were fed the same amount in the big picture, the weekly-fed group grew much more quickly than the other. Since many guidelines for raising reptiles are anecdotal, this provides a baseline by which you can adjust your feeding regimen according to the growth you desire for your boa.
Best Feeding Regimen For Growing Boas
To support a healthy growth rate for your red-tailed boa, you will need to follow a consistent feeding routine. As you might expect, the guidelines for providing a healthy diet for a boa will change as your boa ages.
However, for all ages, ensure that you are only offering prey items that match your snake’s girth (specifically, the part of their body with the widest diameter). Anything larger than that will introduce severe digestive complications.
You can then adapt the frequency of feeding to your boa’s age. The older and larger the boa the less often it needs to be fed.
- Baby Boa Constrictors should be fed every 5-7 days.
- Be mindful of the type of meal you’re providing your babies. Some experts will occasionally feed fuzzies (mice with fur) and hoppers to young snakes, while others suggest restricting their diet to pinkies. You can feed all of these, just not all at the same life stage. Hatchlings should only be given pinkies, and you can work up to hoppers, fuzzies, then adult rodents as they age.
- Adult boas should eat once per 7-10 days.
- Adults can handle being fed larger adult mice or rats. Whether you feed your snake mice or rats at this stage (or in their younger years), ensure that it is pre-killed so it cannot inflict any harm upon feeding.
You are not restricted to feeding rats or mice exclusively as your boa grows. Some snake owners have claimed that their boas grow better on a diet consisting largely of rats; however, you can determine what is best for your snake as you get to know it over the years. In all cases, remember that research has shown that smaller, weekly meals are much more beneficial for their growth than larger, less frequent meals.
Enclosure Sizing Requirements for Large Boa Constrictors
One of the worst (and most expensive) mistakes you can make as the owner of a red-tailed boa is purchasing an enclosure that is too small for your snake’s current and future body size.
As mentioned above, your snake will only be about 2-2.5 ft long as a baby. However, you should not base the enclosure size on this life stage. Instead, predict your baby boa’s adult length and optimize the enclosure size for that length.
You do not have to estimate their size too far into the future. Instead, prepare their housing for how large they will be about two to three years into the future. So, for example, consider the average baby red-tailed boa size. From the starting length, you can reasonably expect your boa to grow to 6 feet in a few years.
Based on this estimate, a suitable enclosure for the snake’s juvenile years would meet the following standards:
- 4 ft long x 2 ft wide x 24 inches high
- Remember that temperature also plays a critical role in your boa’s growth rate. With this in mind, you will need to maintain temperatures between 80-92 degrees Fahrenheit.
- Note: Temperatures that are too close to 70 degrees are hazardous to your boa’s health. Not only will this increase their risk of developing a respiratory infection, but it will also significantly slow their growth.
As your snake grows, you will need to increase its enclosure’s size to keep them comfortable and healthy. When increasing the size of their terrarium, remember that one snake requires a minimum of 10 square feet of floor space for a positive, low-stress living experience.
However, the ideal adult boa constrictor enclosure should be 8 ft x 4 ft x 4 ft.
Boa Water Bowl Sizing
When shopping for your snake’s terrarium, remember that you will be choosing a size that is not only appropriate for their length but spacious enough for the accessories, too. One of those necessary accessories is the water bowl.
Too few beginning snake owners fail to consider the significance of the water bowl’s size in their red-tailed boa’s health and safety. Not only is this element essential to the maintenance of their hydration, but your snake will enjoy soaking in their bowl as well.
It will also contribute to the humidity in the terrarium, so you’ll need to ensure that it is big enough both for your snake’s body and to provide enough moisture to the enclosure without drying out.
To determine the appropriate size for your snake’s water bowl, take a look at their body size. Compare the diameter of the bowl to their approximate width while sitting comfortably curled up. (Your snake won’t always curl themselves up in the bowl. At times, they will only submerge part of their bodies. Still, you want to give them as much room for comfort as possible.)
For all bowl sizes, ensure that the bottom of the bowl is wide enough to prevent tipping. Additionally, don’t buy a bowl with sides that are too high, as your snake might become trapped, especially at a young age.
Are Boa Constrictors Too Large For Beginners?
Boa Constrictors are often recommended as a beginner species for prospective snake owners. This takes many people by surprise, primarily due to the boa’s size.
However, keep in mind that the snake’s size is not representative of the challenges you may face when raising your pet. Thus, a smaller snake does not necessarily mean you’ll have an easier snake-rearing experience.
That said, as someone who has owned a boa constrictor, I would put them at the intermediate level of difficulty. This is due primarily to their medium to large size. If you have never owned a snake I would probably suggest a ball python boa.
I have an article comparing ball pythons vs red-tailed boas if you would like to find out more. I have owned both species and think they are both amazing pets. However, ball pythons are just a bit more manageable for first-time owners.
While they are a fairly resilient species, they are more susceptible to respiratory infections than many other domestic snakes. Keep up with their veterinary care, and you’ll be just fine!
Is The Boa Constrictor The Right Sized Snake For You?
Boa constrictor size can vary from snake to snake. That said, red-tailed boas typically grow to about 2-3 m (6.5-10 ft) long.
On average, females can grow up to 6-7 ft (1.8-2+ m) in their first three years of life, whereas males will reach about 4-6 ft (1-1.8 m). A red-tailed boa’s size is directly influenced by external environmental factors, including temperature and feeding.
It is best to feed your boa once a week to support an average growth rate. You can stretch out this feeding frequency a little bit as your boa grows. You’ll have to upgrade your boa’s enclosure as it grows; however, the ideal enclosure should be about 4 feet x 2 feet x 24 inches in its first few years of life.
A full-grown adult, however, will require an enclosure that is 8 feet x 4 feet x 4 feet.