How to Tell if an Iguana is Male or Female? (4 Simple Methods)

Iguanas, like many other reptiles, aren’t born with the obvious physical distinctions between males and females that many animals have. It’s actually quite a challenge to tell the sex of a hatchling or young iguana; they’re practically identical! However, as they grow and mature, some characteristics start to become more apparent.

From the age of about 18 months to 2 years, our iguana friends begin to show noticeable differences, and that’s when the guessing game starts to get a lot easier.

Males usually grow faster and become larger than females, and that’s your first clue. But it’s important not to jump to conclusions based solely on size; after all, we humans come in all different sizes, and it’s the same with iguanas!

Physical Characteristics of Male vs Female Iguana

During the baby and juvenile stage, male and female iguanas look the same. However, as they reach sexual maturity, male iguanas undergo physical transformations and develop distinct physical characteristics.

The timing of sexual maturity varies among different iguana species, typically occurring between 1 and 4 years of age. Prior to this stage, the only way to successfully determine the sex of an iguana is through the assistance of a veterinarian who can probe the cloacal vent.

Once an iguana reaches sexual maturity, distinguishing between males and females becomes easier based on their specific physical characteristics.

Physical Traits of a Male Iguana


The first thing to look at when trying to determine the sex of an iguana is their physical characteristics. Male iguanas typically have a few distinct traits that set them apart.

  1. Size: On average, male iguanas are larger than females. They tend to grow longer and have a more robust body structure. If your iguana is quite sizable and imposing, there’s a good chance you’re dealing with a male.
  2. Dewlap: This is the large flap of skin that hangs from the iguana’s neck area. Both male and female iguanas have dewlaps, but in males, they’re generally larger and more pronounced. Think of it as a fancy lizard collar!
  3. Nuchal Crest: This is the row of spines that run down the iguana’s back, starting from the neck. Male iguanas typically have longer, more prominent spines compared to their female counterparts.
  4. Femoral Pores: These are small bumps located on the underside of the iguana, on their inner thighs. In males, these pores are larger and more noticeable. They secrete a waxy substance during the breeding season, which is another sign you’re looking at a male iguana.
  5. Spikes – Male iguanas have longer spikes on their heads and along their backs.
  6. Hemipenal bulges – Male iguanas have two hemipenal bulges on their belly near the tail.

Physical Traits of a Female Iguana


Female iguana will have the following physical characteristics:

  1. Size: Typically, female iguanas tend to be smaller than their male counterparts. The ladies of the iguana world usually reach an average length of 5 to 7 feet. Might seem like a small detail, but once you’ve lived with a few iguanas, you’ll appreciate the difference!
  2. Head: Moving on to the next tell-tale sign – the head. Female iguanas usually possess a more streamlined, slender head compared to males. They also lack the significant jowls (the cheek pouches) that male iguanas sport.
  3. Femoral Pores: Femoral pores – small bumpy lines located on the iguana’s inner thighs, can also hint at your iguana’s gender. In females, these pores are smaller and less conspicuous. But in males, they’re larger and more pronounced. Once you’ve observed a male iguana’s femoral pores, you’ll never confuse them with a female’s!
  4. Spikes – Female iguanas will develop spikes only on their backs, and not on their heads as males do.
  5. Dewlap – The dewlap and jowls on a female iguana are smaller than those on a male.

Breeding Season Changes in Male vs Female Iguanas

Another way to tell if an iguana is a male or a female is by observing their behavior during the mating season.

Male Iguanas During Breeding Season

During breeding season, male iguanas go through a significant transformation. Physically, they often exhibit increased body size and heightened color intensity, particularly in the dewlap, which is the loose skin found beneath their necks.

Males might also display more aggressive territorial behavior, often marked by head-bobbing, tail-whipping, and even attempts to bite. It’s quite a spectacle but can be a little disconcerting if you’re not prepared.

Female Iguanas During Breeding Season

Just like their male counterparts, female iguanas also experience notable changes during the breeding season. Females may exhibit physical changes such as weight gain—this is due to the development of eggs, even if they’re not fertilized. Behaviorally, females may become more reclusive and may start looking for nesting sites.

Temperament Differences between Male vs Female Iguanas

To start with, it’s important to note that iguanas, just like us humans, have individual personalities. However, there are some general patterns that we can observe when it comes to their behavior based on whether they are male or female.

Male iguanas are typically more territorial than females. They may show dominance when another iguana (or sometimes even a pet of a different species!) enters what they perceive as their territory. On the other hand, female iguanas are usually more placid. However, they can be protective if they are looking after their eggs.

Male Iguana Behavior

Diving deeper into male iguana behavior, you may find Spike’s mirror-dancing routine amusing. This is a common behavior among male iguanas, where they repetitively bob their heads, especially when they see their reflection. It’s their way of showing dominance and can be more pronounced during the breeding season. But don’t worry, this is normal and an important part of their natural behavior.

Female Iguana Behavior

Switching gears to our lady iguanas, Luna, my female iguana, is generally more docile and easy-going. However, she can get a bit defensive during her nesting period, which is also a natural instinct. They do this to protect their potential offspring.

Differences in Health Conditions in Male vs Female Iguanas

Before we move on to the gender-specific health issues, there are several common conditions that both male and female iguanas can encounter.

  1. Metabolic Bone Disease (MBD): This is a common ailment caused by improper diet, particularly a lack of calcium. Symptoms include soft or misshapen bones, lethargy, and difficulty moving.
  2. Parasitic Infections: Internal parasites are a common issue in iguanas. These unwelcome guests can lead to weight loss, poor appetite, and unusual feces.
  3. Respiratory Infections: These can be caused by improper temperature or humidity levels in the iguana’s environment, leading to symptoms like difficulty breathing, loss of appetite, and lethargy.

Now, let me share some insights into the unique health issues that male and female iguanas can encounter.

Male Iguana Health Conditions

Male iguanas are quite the sturdy creatures, but they’re not without their specific health vulnerabilities.

Hemipenal Prolapse: This is a condition where a male iguana’s hemipenes (reproductive organs) become stuck outside of his body. It’s quite a scary sight to see, believe me! Prompt veterinary care is crucial to prevent severe complications.

Female Iguana Health Conditions

Our lady iguanas, on the other hand, have a whole different set of health conditions to keep an eye out for.

Egg Binding: Also known as dystocia, this happens when a female iguana has difficulty passing her eggs. It’s a severe condition and often requires veterinary intervention. I remember when my own girl, Izzy, had this issue last year. The vet was a lifesaver!

Pre-ovulatory Stasis: This occurs when the follicles stop growing before the eggs are laid, causing the iguana discomfort and potentially leading to infection.

If for some reason you are still unable to sex your iguana here is a video for you:

How to sex iguana made easy ( how to tell male from female iguana )


The comparison between male and female iguanas highlights several distinct characteristics and behaviors that set them apart. While male iguanas often possess larger size and more prominent physical features, such as dewlaps and spikes, females tend to exhibit more subdued appearances.

Moreover, their behaviors differ, with males displaying territorial tendencies and engaging in impressive displays during mating season, while females focus on nesting and reproductive processes.

Filled under: Lizards

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