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Herp Everted Hemipenis

I noticed my lizard has a large bump on his underside near where the tail connects to his body.

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Can you help me? I have a male leopard gecko, and yesterday while feeding him, I noticed that he has a large bump on his underside near where the tail connects to his body. It was somewhat off-center to his left and has sand stuck to it, so it must be wet. It is not red. I saw him try to lick it and he did not eat. I’m hoping he ate later. I fed him about 10 minutes before turning in for the night. I have another leopard gecko in the same tank, and she looks fine and is eating. Should I separate them? What is the large bump? Do I need to go to a vet? What can I do? I can send pictures if necessary.

My suspicion is that your male leopard gecko has an everted hemipenis that has chronically prolapsed. Males have two copulatory organs. Each one called a hemipenis (together they are called hemipenes), and normally, they are tucked into two pouches. In many lizard and snake species, you can see the two bulges behind the cloaca on the underside of the tail.


If the hemipenis is used for copulation, it will usually retract afterward with no unfortunate effects. However, in your case, something happened after the hemipenis was everted, and it got “stuck” out. For example, an everted hemipenis dragged through the sand and cage substrate, will swell, making retraction through the cloaca impossible.

At home, you can clean the area with warm soapy water, or better yet, saline. You can use the contact lens saline, which is available for about a dollar a bottle. Once it is clean, you will need to make an appointment with a herp vet who can assess the situation and decide the proper course of therapy.

If the hemipenis is damaged beyond repair, it might be necessary to have the tissue amputated. A male leopard gecko can still copulate and successfully breed with a female if he has one functioning hemipenis, so amputation of the injured one won’t hurt his breeding capacity. In some cases, using a hygroscopic agent (such as sugar) to draw the fluid reduces the tissue swelling, so the hemipenis can be cleaned, disinfected and replaced in the sac inside the cloaca. Often, a purse-string suture is used to help hold the hemipenis in place during healing, but the lizard can still pass droppings normally. This suture is usually removed in 3 to 5 days.

Of course, I am making an educated guess as to what your leopard gecko’s problem is. For a clear diagnosis, you will need to have a herp veterinarian examine your lizard. Please make an appointment today.

Margaret A. Wissman, DVM, DABVP has been an avian/exotic/herp animal veterinarian since 1981. She is a regular contributor to REPTILES magazine.


Need a Herp Vet?
If you are looking for a herp-knowledgeable veterinarian in your area, a good place to start is by checking the list of members on the Association of Reptilian and Amphibian Veterinarian (ARAV) web site at www.arav.com. Look for DVMs who appear to maintain actual veterinary offices that you could contact.