Knowing what the sex of your leopard gecko is can be extremely important. Without knowing if you have a boy or a girl, how would you even know what to name your gecko, right? Not to mention that if Sasha turns out to be a boy, then he and Zanzibar are going to have a rough go of it—males don’t like other males! Then there is that mental shift you have to make when you believe that Phil is a boy until you realize that he is really Phyllis and you never quite feel the same about him—uh, her. So, we have had plenty of people asking us how to tell if they have a boy or a girl gecko.
One thing that most people find interesting about leopard geckos is that the incubation temperature has a huge impact on the gender of the animal. The lower incubation temps—82 degrees—yield females, while the higher temps—88 degrees—yield males. Middle temps yield a combination of males and females. This is why you see some people referring to geckos as TSMs or TSFs—the TS stands for “temp sexed.” Still there is always the chance you have been duped, so you really need to wait about 3 or 4 months to tell for sure if Mike is really Mike. As the gecko matures, the boy parts start to show. If no boy parts, you have a female—makes sense, right?
If you are not sure what you have, look at the gecko’s under side—also called the ventral side, at the area between the two back legs and just at the base of the tail. A male will form two hemipenal bulges right at the base of the tail, below the vent. A male will also develop a v-shaped row of pores, called pre-anal pores. They use these pores to scent their territory. As a result, you will sometimes see a waxy buildup at these pores. Females don’t have the bulges and the pores are very small in comparison and they do not have the waxy buildup.
This is what you will see:
Congratulations! You are a proud owner of a gecko that is either a boy or a girl, and you can tell the difference!