How Big Do Iguanas Get? Growth Rate, Size & Growth Chart

Iguanas have been enjoying increasing popularity among pet owners due to their friendly qualities. If you’re looking to keep an exotic pet, you might want to consider an iguana. Before purchasing one, one of the questions that one needs an answer to is: how big do iguanas get?

Keeping an iguana can be tasking, especially for pet owners with little experience. Iguanas require special care and even more specific environmental conditions to survive.

The required foods and environmental conditions for iguanas are dependent on how big it gets. This is why it is important to learn the potential size of your little iguana to plan.

In this article, you’ll learn how big iguanas get, how fast they grow, and how you can help your iguana grow to its potential size.


How big do Iguanas Get

How Big Do Iguanas Get?


While you’re most likely to only hear about pet iguanas as being ‘iguanas,’ there’s a lot more to it.

Pet iguanas are of five different types, and they all grow to varying lengths and sizes throughout their lifetime. This makes the question of how big iguanas get a bit tasking to answer.

In this section, we’ll list every kind of pet iguana that you can come across, as well as their lifespan and their potential sizes.

  1. Green Iguanas

If you’ve recently seen someone with an iguana, it’s probably a green iguana. They are easily the most common iguana breed you can find in the United States, and they also grow quite large.

Most people keep the green type of iguanas due to their friendly personality and attractive look.

Green iguanas can grow as long as 7 feet, weighing a maximum of 20 pounds. They grow to this size in around 20 years, which is their average lifespan.

If you’re planning to keep a green iguana, you should be ready to handle a relatively big pet for the next 20 years.


  1. Blue Iguanas (Grand Cayman)

While blue iguanas don’t grow quite as long as green ones, they get about 10 pounds heavier on average.

Blue iguanas are easily one of the most common worldwide, but they’re not as friendly as their green counterparts.

They live anywhere from 20 to 40 years, and they get to about 5 feet long at most. Their weight maxes out at 30, and they enjoy climbing and digging.


  1. Rhinoceros Iguanas

Rhinoceros iguanas are as weird as they sound. They come in green, brown, and grey colors, and they’re relatively smaller than other kinds of iguanas.

Rhinoceros iguanas are the most tasking to keep, with defined environmental needs. They also bite when provoked, and a bite from a rhinoceros iguana is never a pleasant experience.

They grow up to 4 feet in captivity, and they can weigh as much as 10 pounds. Surprisingly, they can live for up to 40 years in such a tiny body.

They are also one of the friendliest iguanas you can keep if that is so important to you.


  1. Desert Iguanas

Desert iguanas are among the best for first-time keepers, as they are more docile than most other iguana species.

They get longer than most iguanas but manage to weigh relatively less. An adult desert iguana is about 15 inches long on average, and it lives for 15 years on average.

While they’re mostly docile, they can and will bite if they feel threatened or overheated.

Interestingly, desert iguanas can also change color to regulate their body temperatures.


  1. Black Spiny Tailed Iguanas

As expected, black spiny-tailed iguanas have spines running down their tails, and they’re mostly black.

They drop their tails pretty easily, so you’ll want to think twice before holding a spiny-tailed iguana by its tail.

The black spiny-tailed iguana grows to around 3 to 5 feet and lives for 15 to 25 years.


How to Make Your Iguana Grow Faster


If you want to get a pretty enormous iguana to show off to friends, you’ll need to know what to do to make it work; and be ready to dedicate the required effort and supplies.

While we can’t help you dedicate the effort, we can help you with what to do to make it work. Here are some tips that can help increase the lifespan of your iguana, while making them grow faster.

  1. Feeding them properly

Nobody will be surprised to learn that food is the major factor contributing to the growth of an iguana. If iguanas eat well, they will potentially live longer.

While iguanas might look strikingly similar to some carnivores (ahem, crocodiles), they are not carnivores. Iguanas need no nutrients from plants to survive.

Contrary to popular belief, iguanas should not eat crickets and other insects. If these insects are part of your iguana’s diet, you’re severely diminishing the lifespan of the reptile.


How big do Iguanas Get


  1. Environment

Iguanas don’t cope well in captivity; take it or leave it. They can potentially live their lifespan and grow to their full potential, but the chances are lesser than those in the wild.

This doesn’t mean you shouldn’t try to create a favorable living environment for your iguana. In fact, the more you can simulate the natural environment of an iguana, the better it will cope.

You cannot provide a cage that’s large enough for an iguana because they love to roam. They enjoy climbing and digging the ground and fighting. Can you provide the needed supplies to make these tasks possible in that limiting gallon?

While you might be unable to simulate their natural environment accurately, you should try to keep the conditions of the simulated environment as close to normal as possible.


  1. Lighting

Iguanas require special lighting conditions; this is one of the reasons why they are difficult to keep.

An iguana enclosure should have UVA and UVB light sources. UVA light simulates the natural sunlight, keeping the enclosure as real-to-life as possible, while UVB light sources help the iguanas manufacture essential minerals.

The sun is the best UV light source for your iguana if it is unobstructed by the glass.

For maximum health, your iguana has to leave its cage to bask in the sun once in a while.


Iguanas Growth Chart


Age SVL Body Length (Inches)  STL Body Length (Inches) Weight (Pounds)
When Hatching 2.5-3.5″ 6-9″ 0.2 lbs
Year 1 8-9″ 20-27″ 1-1.5 lbs
Year 2 11-12″ 28-36″ 2-4 lbs
Year 3 12-14″ 30-42″ 4-6 lbs
Year 4 24-16″ 35-48″ 5-8 lbs
Year 5 18-20″ 45-60″ 10-15 lbs
Year 6 20-22″ 50-66″ 14-18 lbs
Year 7+ 20-24″ 50-72″ 15-20 lbs



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You can do anything better if you prepare for it. Preparing in advance for your iguana is crucial to help it grow to maximum size and weight.

To determine if your efforts are working, you need to know the maximum size and weight of the iguana.

This article is all you need to learn how old iguanas can get and how you can help them grow as big as possible.