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Gecko Mating Problem

My male reptile attempted to mate with my female for the first time. What happened next was that his testicle seems to have popped out.

My lizard has not eaten since I got her, and she also has a bottlejaw, which I think is from hypoproteinemia due to parasites. Can you help?
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My male leopard gecko attempted to mate with my female for the first time. What happened next was that his testicle seems to have popped out. At first, I thought it was the penis. But, after 10 minutes, it didn’t go away, and he started biting at it, so I figured something was wrong.

Will you please tell me what to do? Also, what should I do to prevent infection? There are no vets who know how to treat reptiles in my area. However, if I needed to, I would definitely take my gecko to a knowledgeable herp vet outside the area. Is there something safe enough I could do for him on my own?
-Jeremy Maksimovic, Maryland


I am glad that you got your geckos to mate. Sounds like they had a wild time, especially if one of the male’s testicles fell out in the process.

Actually, I seriously doubt that one of the testicles fell out. There is no way that could happen (unless you believe what you read on the Internet). If it did, your leopard gecko most likely would have died.

Lizards and snakes have two copulatory organs, called hemipenes (“hemipenis” is the singular term, not “hemipene” as is commonly written). The turtle only has a single organ, called a penis (as it is called in mammals). The organs reside inside the cloaca, tucked into the tail in snakes and lizards, and in the cloaca, but forward within the base of the tail, in turtles. In turtles the single organ is everted, and in snakes and lizards only one of the two organs are extruded during mating.

The hemipenis or penis will usually only come out during mating behaviors. However, young males will occasionally protrude their penis for no apparent reason. Infection, parasites, injury, constipation and other medical reasons may also cause a hemipenis or penis to protrude.

In the case of your leopard gecko, it is obvious that the prolapse was a result of the mating. The organ may have been injured during the event, and, as a consequence, was not able to return to its natural position.


Most of the time the problem can be identified and treated. The hemipenis or penis can be returned to the tail base and there are usually no serious consequences. In some cases, a temporary surgery, called a purse-string suture, may be necessary to ensure that the organ stays where it belongs and has ample time to heal.

In cases of severe injury the hemipenis or penis may need to be amputated. The penis of a reptile is only a reproductive organ, not a urinary organ. So, there is no risk or problem with urination.

If you see this happen again, the most important thing to do is keep the prolapsed organ protected. Cover the cloacal region with a moistened, soft bandage. If you have an antibiotic cream, such as neomycin, you can gently cover the prolapsed tissue.

The prolapse needs to be replaced as soon as possible. If you are not comfortable doing this yourself, then take the animal to a veterinarian (preferably a herp veterinarian) immediately. At the bottom of this column there is a referral to the Web site for the Association of Reptilian and Amphibian Veterinarians (www.ARAV.com). Once on the site, you can locate a herp vet in your area.


One very important note before closing: There are other organs and structures that can prolapse out of a cloaca. You must be able to identify the tissue that is hanging out – and damaged or injured tissue can be difficult to identify. If you have any questions or doubts, don’t try to treat this on your own, take the animal to the veterinarian.

About the Author
Dr. Mader, an avid amateur herpetologist, is a board certified veterinary specialist. He received his Doctor of Veterinary Medicine degree from the University of California, Davis in 1986 after earning a Master’s degree in Animal Behavior in 1982. After graduation from Veterinary School, Dr. Mader completed a residency in Primate and Zoo animal medicine. During his veterinary and residency training, Dr. Mader’s areas of special interest were in the pharmacology of antibiotics in exotic pets. While living in Southern California, he owned a small animal/exotic practice for 9 years. He now owns the Marathon Veterinary Hospital, a Specialty/Referral Veterinary practice in the middle of the Conch Republic. In addition, Dr. Mader is the veterinarian for the Marathon Sea Turtle Hospital, the Monroe County Zoo and the Key West Aquarium. Dr. Mader is an internationally acclaimed speaker and is on the review boards of several scientific journals. He has published numerous articles in scientific and veterinary journals, national magazines, newspapers, book chapters and is the author/editor of the Saunder’s publication Reptile Medicine and Surgery. Dr. Mader has been a columnist and contributing author to REPTILES magazine since its inception.

*This article first appeared in the April 2004 issue of REPTILES magazine.*