Gecko | Facts

Is Your Leopard Gecko Male or Female? (Look at Its Vent!)

If I had a dollar for every time I heard of a new gecko owner finding out their male gecko was female—and vice versa—I’d be rich! You see, what many people forget to consider is that not all geckos are the same. So it can be really difficult to determine your gecko’s sex at home.

The two most distinctive features that differentiate a male from a female leopard gecko are the pores and bulges near the base of their tails. Male leopard geckos have a V-shaped row of tiny pores which is subtle in female geckos. Female leopard geckos have flat tail bases while male geckos have also two evident bulges below their vents.

But what if you still can’t figure out whether your gecko is a girl or a boy? Should you give up trying? You can even get your exotic vet to definitively determine your gecko’s sex. Keep scrolling to find out how to tell if your gecko is male or female!

Sexing Male vs Female Leopard Geckos (2 Signs!)

Temperature-sexing in leopard geckos during egg is not always guaranteed and so owners must inspect two features located near their vent: femoral pores and tail base.

A leopard gecko’s sex is generally determined by the temperature it is incubated while it’s still developing in its egg.

So if you bought your gecko from a breeder, then you’d likely know whether you have a boy or a girl right from the start. But even then, there are chances when you’ll realize that your supposedly female leo is actually a male and vice versa.

This is because egg-incubation temperatures don’t give you a 100% guarantee of your leo’s sex. In fact, this is true for most, if not all, other geckos whose sex is determined by environmental factors such as temperature.

So you need to familiarize yourself a leo’s secondary sex characteristics—which are quite obvious.

However, leopard geckos have neither cloacal spurs nor calcium sacs–both [1]. When I mention calcium sacs, you may be picturing the “armpit bubbles” that some leos develop but this is not actually their endolymphatic sac.

Learn more about this in our article discussing armpit holes.

1. Femoral Pores

Leopard geckos that are male normally have enlarged femoral pores with waxy secretions, whereas females either have very small and faint pores or none at all.

Depending on where this row(s) of pores are found, their name may change [2]. In geckos, however, these U-, V-, or W-shaped pores are interchangeably called preanal, precloacal, and femoral pores since they are positioned above the vent and between their hind legs.

Now, I often hear and see people saying that female leos don’t have femoral pores. But this isn’t entirely true. Nevertheless, some newbie pet parents are made to believe that only male leos have pores—leading to many wrongly sexed leopard geckos.

In reality, female leopard geckos can have femoral pores. When compared to a male’s pores though, female pores are commonly smaller and less noticeable at first glance.

Oftentimes, you’d also see a waxy cream or yellow semi-solid substance coming out of the male leopard geckos’ vent. These secretions are believed to be used for:

  1. Helping males cling to females while mating
  2. Facilitating or hindering breeding
  3. Marking or claiming territory
  4. Recognizing themselves and others

Some scientists also believe that these may serve no important purpose for geckos at all—which could explain why not all females secrete such waxy plugs in their pores. Only unmated female geckos seem to produce these supposedly pheromone-rich discharges.

Male leopard geckos, on the other hand, produce more waxy plugs in their femoral pores during the breeding season. Hence, experts believe that this is primarily involved with mating.

Can these plugs get stuck? Find out in our article on gecko sperm plugs. 

To make things more interesting, some studies show that a male lizard’s femoral pores can shrink after they get castrated [3]. As a result, their pores become more similar to that of females which, again, further complicates sex determination by regular gecko owners.

2. Tail Base

Generally, male leopard geckos have pronounced hemipenal bulges below their vents, on their tail bases. Meanwhile, female leopard geckos have relatively flat tail bases.

Unlike humans, male geckos have a pair of penis. These are called hemipenes and are usually kept in pouches within their vents—only popping out when they are ready to mate.

In other words, leopard geckos keep their hemipenes tucked away most of the time. During such times, the base of their tails generally looks as though they are swelling.

This is what people refer to as the hemipenal bulge. Upon a closer look, you can even make out a slight dip in the middle of their bulge, making it look like they have 2 ball sacs by their vents. Funnily enough, I know some people call it their gecko’s “man bits.”

Conversely, female geckos, of course, don’t have hemipenes tucked away within their cloacas. Hence, their lack of hemipenal bulges. So if the base of your gecko’s tail—right below its vent—is pretty flat and even, you probably have a lady leo in your care!

However, one study showed that female leopard geckos can develop not only bulges but also actual hemipenes through weeks-long administration of testosterone in high doses [4]. Don’t worry though, this is unlikely to happen to your pet geckos at home.

A Curious Case of Female Geckos With Hemipenes
A Curious Case of Female Geckos With Hemipenes

But female leopard geckos may also develop a lump underneath their vents due to excess fat if you are preparing it for the breeding season or if it’s obese. This may be mistaken for hemipenal bulges.

How Do You Know If Your Gecko is Male or Female?

To determine a gecko’s sex, lay them on a clear glass or plastic container, cover with a soft cloth on top, and examine them with a jeweler’s loupe. Geckos must be sexually mature, about 12–40 grams and 6–12 months old, for proper sex determination.

Most geckos don’t have readily obvious physical differences between sexes. Though male geckos typically have bigger heads and bodies, it’s hard to know if your gecko falls within the average or above it, especially since geckos are fed more as pets.

The majority of them are also pretty small making sex determination with your naked eyes super challenging, even more so with small species like day geckos. A loupe like this one on Amazon is important in such cases as acts as both a flashlight and magnifying glass.

Experienced keepers and breeders can sex their geckos using their bare hands without stressing out geckos. However, many newbies keep their geckos on their backs for a long time to properly examine and take pictures of their geckos which can be very stressful.

I have also seen some people pull on their gecko’s tail while trying to sex it—which is pretty dangerous. When feeling threatened, geckos are likely to drop their tails and not all species can regenerate them.

Young and beginner pet parents often make the mistake of trying to sex a hatchling or juvenile gecko as well. This is virtually impossible since they don’t develop prominent secondary sex characteristics (e.g., pores, bulges) until they mature into adults.

You can generally distinguish an adult gecko from a sexually immature one by knowing not only their age but also their overall weight. Their snout-vent-length or SVL can also be considered but isn’t as important for sex determination.

Are All Mourning Geckos (Lepidodactylus lugubris) Female?

Mourning geckos are a species that reproduce asexually by cloning themselves. But despite being a predominantly female species, mourning geckos can produce infertile male geckos since females have the sex chromosomes for both.

Like tokay geckos, mourning geckos are also in the Gekkonidae family and have their sex dictated by genetics instead of temperature [5].

However, instead of having XX and XY sex chromosomes, mourning geckos possess ZW and ZZ sex chromosomes for females and males respectively. This is why despite being known as an “all-female” species, mourning geckos can lay males as well.

Plus, since these amazing geckos are capable of the so-called “virgin birth” or parthenogenesis, they can continuously lay fertile eggs without the need for sperm.

Getting only duds? Discover the reasons why geckos lay infertile eggs!

What’s the Most Accurate Way to Determine a Gecko’s Sex?

The most accurate way to determine a gecko’s sex is through clinical methods of assessment which can only be done by an experienced exotic veterinarian. Such methods include illumination of the tail base and ultrasound.

Depending on what specific gecko you are keeping a vet may recommend different methods of clinical sex determination [6]. Some procedures are more invasive than others so be sure to ask your local reptile vet about anything you’re worried about.

A veterinarian can accurately sex a gecko through:

  1. Illumination. Using a light source to detect the presence or absence of hemipenal blood vessels in a gecko in a dark room.
  2. Popping. Also called manual eversion, this requires gentle massaging of the post-cloacal area to let out tucked-in hemipenes.
  3. Hydrostatic Eversion. Applying a saline solution by the base of a gecko’s tail with an injection to have the hemipenes pop out if present.
  4. Cloacal Probing. Carefully inserting a sexing probe into the gecko’s cloaca to see if hidden hemipenes are present.
  5. Radiography. Taking radiographs, more commonly known as X-rays, to inspect the endolymphatic sacs and reproductive organs of geckos—at times using special dyes.
  6. Ultrasound. Viewing a gecko’s reproductive organs and the presence or absence of developing eggs.
  7. Endoscopy. Inserting a small endoscope into a gecko’s body to determine whether it has testicles or ovaries—usually requires anesthesia.

Now, you might think that these procedures are not worth the extra cost since sex doesn’t affect husbandry standards for geckos. However, this isn’t completely really true.

By knowing your gecko’s sex you can prepare safety precautions to avoid sex-specific conditions which can be deadly.

Providing lay boxes for female geckos even when you have no plans of breeding them can not only decrease but also eliminate the chances of egg-binding. Ensuring an appropriately humid tank, on the other hand, can prevent plug impaction in male geckos.

Further Questions

Can you distinguish a boy gecko from a girl by their behavior?

Basing a gecko’s sex on its behavior alone is not advisable as it can vary a lot among individuals regardless of sex. Moreover, although male geckos are considered aggressive, especially when housed together with other boys, the same is true for female geckos grouped together with girls in one tank.

Why is your gecko licking its private parts?

A gecko may lick its private parts to groom itself or relieve pain and discomfort in the area. If there is unusual swelling and discoloration in the area, seek immediate veterinary attention and treatment as these can be signs of a bacterial infection or prolapse.

Summary of Is Your Leopard Gecko Male or Female

The presence, appearance, and size of a leopard gecko’s preanal pores and tail base can help owners determine whether their geckos are male or female at home. For easier assessment, a loupe is recommended as it allows keepers to better see a gecko’s features.

However, owners must keep in mind that a gecko’s secondary sexual characteristics can vary greatly according to their species. Even within a single species, male and female geckos have individual differences that can make physical sex determination confusing.

So when keepers and breeders can’t confidently determine whether their gecko is female or male, clinical methods performed by a veterinarian may be necessary. Otherwise, owners may be unaware of possible issues such as impacted plugs and egg-binding which geckos may experience depending on their sex.








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