Do Iguanas Lay Eggs? Facts, Tips, Breeds


I’m going to answer a question that does get asked quite a lot, and that’s the situation about Iguanas and whether or not they lay eggs. Of course, as an owner (or prospective owner), this is the type of information that you need to be aware of, so what’s the answer?

Iguanas do lay eggs. In this respect they act the same as most other lizards. Iguanas lay anything from 1 to 70 eggs at a time, depending on the breed of the iguana. The majority of iguanas lay between 5 and 20 in one go.

However, of course knowing just this simple fact is just the beginning. In this post I’m going to dive into everything you need to know about iguanas and eggs – how they lay them, where, when, how they are fertilized, the difference between species, and a whole load of other iguana egg facts.

Iguana sitting on rocks

The Issue of Sexual Maturity

First, the female Iguana is only going to lay eggs when she reaches sexual maturity. That’s going to be when she’s around 2 to 4 years. After that, she’s going to lay eggs once a year. 

However, that’s only a rough guide. Some Iguanas do reach maturity even before the age of 2, while others can take longer.

The Basics of Iguanas and Their Eggs

A female Iguana is going to lay eggs, but how many they lay will depend on their species. In general, it’s going to vary from anywhere between 5 and 20 eggs at a time, and that’s quite a big difference.

But there’s another difference, and that’s if you own the bigger Green Iguana. 

While a rock Iguana will lay up to 20 eggs, the Green Iguana is going to lay up to 65 eggs at the one time, and that’s a rather impressive figure.

Think of it this way. If a Green Iguana starts producing eggs when they are 2 years of age, and they live until they are 15, then that’s going to equate to them producing over 800 eggs in their lifetime, so that’s a lot of baby Iguanas.

Generally, a female will lay eggs around 65 days after mating. Then, the size of the eggs she produces will also depend on a number of factors. This can include her age, how big she is, and how well-fed she is.

For most, the eggs are going to measure some 15 mm in diameter, while they will be around 35 mm in length. So, they aren’t too big. Also, they will be either white or an off-white color.

Where a Female Iguana Will Lay Her Eggs

The way in which a female Iguana will lay her eggs is to place them in a warm burrow. Also, they tend to enjoy having the sun hitting them, so if you are trying to breed Iguanas at home, then they will want to lay their eggs to the main light source.

These burrows can be a bit of a problem. The female will dig down into the ground to create the hole. This may be anywhere from 45 cm to 1 m in depth, and in some places they will do this on your lawn, so watch out.

But these guys are smart.

They will look at keeping the temperature of the burrow containing their eggs to anywhere from 77F to 89F.

That is seen as being the optimum temperature for the eggs to then hatch in the future, and it does seem to increase the chances of them doing so successfully.

They do this by effectively burying the eggs. They do leave a small space that acts like an air pocket, as this is something that will then help the baby Iguana once it has hatched.

Also, buying them does mean they are going to keep the temperature pretty consistent, and there’s also a safety element attached to it as well. [Source]

When Will They Lay Them?

The female Iguana is only going to lay eggs at certain times of the year. If we are talking about in the wild, then it tends to happen in late fall, and it goes through to the end of spring. 

Now, I just said about the temperature, so you may be surprised to hear that they tend to lay them in what we would see as the winter, but you need to remember where an Iguana will live in the world.

Those places don’t tend to get too cold, so it’s not a bit issue.

So, what you have here is the female Iguana mating in the dry season, which then leads to their young hatching in the wet season. 

More About Iguana Mating

A quick word about Iguana mating, as it’s different to what you may expect, or what tends to happen with other animal species.

Iguanas are very territorial. They will fight other Iguanas over the area where they are going to live, so having two males in close proximity is not a good idea. 

However, once the fighting is over, it does mean they are ready for mating, but in the world of the Iguana, it’s the female that chooses who she is going to mate with rather than the male making the decision. 

The female will even spend time checking out different males around her area before she goes ahead and makes her final decision. 

It’s also not uncommon for the male to go ahead and mate with several different females during the mating season.

They Don’t Even Need to Be Fertile

But this fact is even more surprising. A female Iguana can lay eggs even when they are not fertile. It seems they will still go through the process of producing them, but clearly nothing can happen with those eggs, as they have not gone through the full process. [Source]

What this means for you as an owner is that your female Iguana will continue to lay eggs every single year.

However, as they have not had any interaction with a male, unless you are specifically trying to breed them, then at least you know that these are phantom eggs.

But that’s perhaps not always the case.

One problem is that a female Iguana can store sperm from a male for several years before it’s used to fertilize an egg.

What that means from your perspective is that it’s possible for the female to have mated with a male before you got her, if you bought her as a more mature Iguana, and then suddenly she produces eggs that lead to hatchlings.

How Long Until They Hatch?

After the female has laid the eggs, it’s going to take between 90 and 120 days for those eggs to hatch and a baby Iguana to emerge. However, don’t think for a second that the female is going to be sitting there on those eggs for all that time.

Instead, a female Iguana may come back and check on them on a couple of occasions, but generally speaking, she’s going to leave the eggs alone, and they will hatch pretty much without her help. 

Also, a single nest may include eggs from several different Iguanas. The females are quite happy to share the spot with others, and this is particularly true if good nesting sites are hard to come by. 

Green iguana on a grass floor with leaves

How the Hatching Breaks Free

When it’s time for the hatchling to emerge from the egg, they do so by using a special egg tooth. This small, sharp tooth is designed to help them poke through the outer shell, and the hatching process then begins. Once free, this egg tooth falls off as its job is done.

From then on, the baby Iguana has to fight for survival, but they are helped by the yolk in the egg.

That yoke provides them with enough sustenance for the first couple of weeks of their life, so it gives them enough time to start to adjust to their surroundings and to get some idea as to what’s going on.

How the Owner Knows The Female is Going to Lay Eggs

So, how do you even know if your female Iguana is going to be laying eggs soon? As an owner, it’s best to be aware of these sorts of things, as it gives you an indication of why there appears to be a change in behavior.

Generally speaking, there are several signs for you to look out for that can indicate that this event is about to happen.

She Loses Her Appetite

One of the first signs is that there’s a decrease in her appetite. This will start around a month before she will lay her eggs. 

With this, you will notice that she may only slightly munches on some greens, and she will only consume a very small amount of water over the course of a day. 

But don’t worry.

This is all because of the space the eggs take up inside her body. She produces so many, and at a reasonable size when compared to the size of her, that she simply doesn’t have as much space to consume as much food.

Her Abdomen Will Grow

Another sign that she is about to lay eggs is that her abdomen is going to grow. This is something that will be very noticeable. Also, if you touch her, you may feel the eggs inside of her, but this is not always possible.

However, if you can see the eggs against her skin, and she has not been interested in food for several weeks, then you can pretty much say that she is going to be laying her eggs in the very near future.

Allowing Her to Nest at Home

Now, I mentioned earlier on that the female Iguana will like to dig a burrow that could be up to 1 m deep in order to lay her eggs. Of course, that’s not possible in her home with you, so what do you do?

You need to provide her with a nesting box in order to at least partly replicate that entire process. It allows her to go through the nest building process, which is important for her.

It’s also going to be another sign that she is preparing to lay some eggs when she suddenly becomes interested in the nesting area and gets to work on it. 

Providing this nesting area is essential. If you do not, then she could develop some problems when it comes to the actual laying of the eggs. 

More on the Nesting Box

As the nesting box is such an integral part in all of this, it deserves more attention.

You want to give her a decent sized nesting box. Also, it should be pretty much enclosed, as this will also give her a sense of security as she goes about building the nest part. 

The key here is to put a separate enclosure inside her home. How big this is going to be does depend on the size of her tank. 

Make sure that the hole to get into the nesting box is on the top. Get the hole to be big enough for her to get in and out without being too stressed. However, don’t make it too big, as you want her to feel that her eggs are still going to be protected, and largely hidden from view.

One other option, which does mean you need to be paying attention to what’s going on, is to put a cloth over part of the hole when she is inside and laying her eggs. This may help reduce the stress she is feeling at this time, and it will make the whole egg laying thing go smoother than planned.

What to Fill the Nesting Box with

But aside from the container, what should you put inside the nesting box? Well, there are certain materials that will work out better for your female Iguana than others.

The ideal mix is going to be some soil that’s used for potting plants, some sand, and some water. That should allow her to dig a hole into which she’s going to place her eggs. 

This, mixed in with the temperature of the tank, should help her feel that she is indeed replicating the entire process of laying her eggs, like she would do in the wild. It’s just sad that they are going to be phantom eggs and that nothing will come of them. 

Helping Her With the Laying of Her Eggs

So once you are aware that she is going to be laying her eggs, what are the other things that you should be doing as a suitable owner? 

Keep in mind that laying eggs is very stressful for the female Iguana. She doesn’t need to have anything going on that will spook her or make her freak out. So, you need to provide her with that sort of safe, comfortable environment as best you can.

Keep an Eye on the Temperature

I mentioned the temperature earlier on, and it makes sense that you need to then keep an eye on the temperature during this time. Try to maintain the temperature toward the higher end of her preferred range, as that’s going to make things that little bit easier for her.

Provide Her with Exercise

During this period of the eggs developing, she’s going to need enough space to exercise, as this also plays an important role in this whole egg development thing. 

Make sure her home is tall and has branches that she can climb up and over whenever she wants. She needs to be able to move around without any problems.

Give Her Calcium

When you first realize that she is going to lay eggs, and it’s still early on in the process, then dust her food with some calcium. She’s going to take calcium from her own bones in order to basically inject it into the development of the eggs. If her calcium levels drop too far, then she may develop some bone issues, so giving her a calcium supplement is very important.

If you are at all concerned with her health at any point through the egg production, and then laying, process, then getting her checked out by a vet is clearly going to be the best option. 

The Summary

So, an Iguana does lay eggs, and she will do so once a year, with up to 65 eggs being laid at any given time depending on the species. Also, she will lay them several weeks after mating. Once she has buried them, she’s going to leave them alone and won’t sit and guard them. 

Eventually, after up to 120 days, the hatchlings will emerge, and the baby Iguana is going to be fully independent right from the very beginning. 

However, when you have a pet Iguana, you want to make sure you provide her with a nesting box to go through the entire process, even though the eggs themselves are going to be infertile. This is all part of the process of her living her life, so as a careful owner, you don’t want to go about upsetting that process at any point.

Barry Gray

Barry is a freelance writer from Scotland. He has written about pets for over a decade, and his work has been turned into a range of ebooks, courses, and material for diplomas. Barry is passionate about all animals, but particularly dogs, fish, rabbits, birds and spiders. You can find out more about Barry at https://mercurypets.com/our-writers/

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