Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Seminal (Hemipenal) Plugs and Seminal Exudates

©1994, 2002 Melissa Kaplan


What Seminal Plugs Are Not
Seminal plugs are not the same things as the plugs in femoral pores. Femoral pore plugs are normal and you need do nothing to or about them unless an abscess form under or around one. In some iguanid and agamid species, the waxy plugs grow longer during breeding season. As the lizard walks, dragging his thighs and the plugs across surfaces, the scent-laden femoral pore plugs are worn down as the male marks his territory.

Seminal plugs, on the other hand, develop inside the inverted hemipenes and should be removed if they are not naturally expelled during defecation. You'll know when it's time to do something about them when they become clearly visible, sticking out through the venter folds.


Seminal Exudates
The sexually mature males of many iguanid, agamid, and some scincid species exude a white sticky rubbery H-shaped substance - you may find it dried on surfaces to a kind of brittle amber color. This is normal and needs no intervention. This exudate is formed in the hemipenes. It may be extruded when the lizard defecates, or on its own. When it is being forced out, the lizard will evert his hemipenes to free the matter, and may rub the hemipenes on the surface the lizard is standing on to get the exudate off.

Seminal plugs tipped with an accumulation of feces.

Seminal plugs
Seminal plugs (see photo above) are hard waxy plugs of seminal fluid and cellular debris that build up in the inverted hemipenes. They have a long, tapered shape, usually with a rounded cap at the end which is closest to the cloaca/vent. When the plugs start protruding from the groove in the hemipenes into the cloaca or the vent, the feces passes along the top of the plug, usually coating that end. Often, the first sign of retained plugs that a lizard keeper sees is what looks like a small clump of feces stuck in the vent. What is actually being seen, however, is the top of the feces-capped plug.

Normally, these plugs, which form usually during breeding season, are expelled naturally during defecation. They may or may not be noticeable when the keeper is cleaning up the urates and feces. When they are extruded by the lizard during defecation (or as an isolated act, as with the melted cheese-like exudate discussed above), they may be so small as to be unnoticed, or may be covered by the feces. If the plugs are not forced out, however, they continue to grow in the inverted hemipene, eventually causing some discomfort.

What does need intervention as soon as they are seen are retained seminal plugs.

Once they grow in length as high up as the vent, the tops of the plugs begin to trap feces when the lizard poops. In time, you will see two pieces of hard smooth poop in the lizard's vent. You can try to remove them yourself. First, soak the lizard in a warm bath. Then using gloved hands or a couple of layers of facial tissue, gently rock one of the plugs from side to side as you gently pull. The plug should pop out. A bit of the hemipene may evert a bit with the plug but the hemipene should retract back into the tail. Repeat with the second plug, if there is one.

When I first wrote this article, there weren't many vets who were familiar with either the exudates or with the seminal plugs. While lack of knowledge about the former is not a problem, it is in the case of the latter - I've heard of vets wanting to amputate the hemipenes thinking there was a problem! This illustrates why it is important to go to a vet who has not only experience working with reptiles but to keeps up with the reptile veterinary literature and research.


Big Lizards, Big Stuff
Keepers of smaller lizards may never see or notice exudates or plugs. The larger the lizard, however, the larger the matter. I see the plugs and cheesy strands from green and Cyclura iguanas, as well as bearded dragons and blue-tongue skinks. In addition to these items, male iguanas may ejaculate during breeding season. They may do this when sexually aroused, or may attack and "mate" with objects such as gloves, stuffed toys, towels, clothing, shoes, or their branches. Seminal fluids may also be seen mixed in with their urates. As with other animals, this is a thick, milky white substance and, in the context of breeding season, is perfectly normal...if not a little obnoxious when they do it on your clothing or bedding!

Right: These are plugs from Mikey, my 7 year old Cyclura. They measure 2.5 inches long, 0.5 inches thick, and .75 inches wide. No wonder he gets a bit cranky as they build up in his hemipenes!

Seminal plugs from Mikey, a 7 year old Cyclura hybrid.


Related Articles


Cloacal and Hemipenal Prolapse

Need to update a veterinary or herp society/rescue listing?

Can't find a vet on my site? Check out these other sites.

Amphibians Conservation Health Lizards Resources
Behavior Crocodilians Herpetology Parent/Teacher Snakes
Captivity Education Humor Pet Trade Societies/Rescues
Chelonians Food/Feeding Invertebrates Plants Using Internet
Clean/Disinfect Green Iguanas & Cyclura Kids Prey Veterinarians
Home About Melissa Kaplan CND Lyme Disease Zoonoses
Help Support This Site   Emergency Preparedness

Brought to you thanks to the good folks at Veterinary Information Network, Inc.

© 1994-2014 Melissa Kaplan or as otherwise noted by other authors of articles on this site