How Can I Tell a Female Iguana From a Male Iguana?

Watch the behavior of the iguana. Male iguanas are more territorial than females and may be seen bobbing their head and doing push-ups more often than females. Also, the males will fight with other males when kept in too small of spaces.

Look at the coloring of the adult iguana. Males in breeding condition may have color changes. For example, with the green iguana, males may become partially orange over their back and sides, report the authors of "Reptiles, Amphibians, and Invertebrates."

Examine the face of the iguana. The face, particularly the lower jaw, may be larger than the female's jaw of the same species.

Look at the underside of the iguana's back leg. Along the underside of the thigh, you will see large circular patches. These femoral pores will be significantly larger in males.

Look at the vent area of the iguana. The vent is located between the back hind legs. In males, you can often see two bumps just below the vent. These are the male's internal hemipenes.

Take your iguana to a reptile veterinarian. Reptile veterinarians experienced with iguanas will be able to definitively determine the sex of your iguana through an examination or DNA blood test. With some species and individuals, this may be the only way to tell if you have a male or female iguana.