Reptiles/Iguana injury


lower jaw bigger
lower jaw bigger  
Hi! My name is Megan. I have an iguana that i would guess is about a year and a half two years old. I noticed about three months ago that the lower jaw of the iguana is much larger than the upper jaw, this happened to my other iguana but it died due to lack of eating. the iguana that has the jaw problem eats and drinks just fine and romes about the cage great, i am just concerned about the size of its jaw and I am not sure what to do about it.

The most common cause of a malformed jaw would be vitamin D or calcium deficiency.  This causes a problem known and nutritional secondary hyperparathyroidism.  In the past it was known as metabolic bone disease (MBD).  The first signs are often malformation of growing bones, swelling (edema) which makes the animal look plumper than it actually is, brittle bones which break easily, and finally, loss of appetite and death.

Green iguanas require strong UVB lighting in captivity.  If fluorescent reptile lights are used for this, they must be within 6 inches of the animal when it is basking, they must be the strongest type available, and they must be replaced every 6 months (the UV coating deteriorates with use).

The new Mercury-vapor reptile lights that produce both heat and UVB are a better choice for green iguanas.  They throw UVB further and last up to 3 years.

In addition to the concern of proper UVB lighting, green iguanas have very intricate dietary needs, and require greens that are high in calcium, and low in oxalates (which bind calcium).  There are good green iguana diets listed online.  Commercial diets are inadequate and dangerous for long-term use, as they often contain too much protein, which destroys iguana kidneys, and can cause abnormal growth as well.

Green iguanas are not recommended for those who are new to keeping reptiles, due to their complicated dietary needs, and huge adult size.

Male iguanas do have large, heavy jaws.


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Donna Fernstrom


My particular focus is on snakes and lizards, but I have a decent smattering of knowledge of turtles and crocodilians as well, plus the experience to get relevant information quickly if I don't have it on hand in my brain. I can answer questions on captive care, diet, breeding, incubation of eggs, starting hatchlings, and more. I am particularly experienced with ball pythons, Lygodactylus geckos and other small lizards with similar care requirements, leopard geckos, and garter snakes.


I am a professional breeder of ball python morphs, Lygodactylus (dwarf) geckos, and mourning geckos. I have begun working with Irian Jaya carpet pythons, and plan to expand to include more gecko species in the future. I also have a background breeding leopard geckos, and have kept several other species of small lizards, snakes, and a water turtle.

Nebraska Herpetological Society (

I have many care sheets published on my own website.

High School Graduate. Extensively self-taught due to high interest in wildlife and reptile care.

Awards and Honors
Fauna Classifieds board of inquiry Good Guy Certification

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