Iguana Skin Color
Color variants, normal changes, and changes due to stress
©1997, 2001 Melissa Kaplan
The green iguanas (Iguana iguana) are so named because, with few exceptions (abnormally colored or patterned individuals found in normal populations), they are green. The green may be deep and dark, pale and multi-hued, have greater or lesser amounts of blue, may have bold or subtle striping, or subtle or bold blotches...but they are predominantly green in color.
These iguanas, which may come from Peru, should not be confused with the many baby iguanas from all over the range who show lots of blue when they are hatchlings. For a year so so, there was a flood of "blue iguanas" in the pet trade, with dealers snapping them and selling them for 3-4 x the price of the "regular" green iguanas. The people who paid more for these "special" iguanas found to their dismay that by the time their "blue" iguana reached a year of age, they were just as green as any other iguana. The true "blue" iguanas look exactly like the green iguanas when the are babies, so picking a blue hatchling is no guarantee that it will retain any blue as it matures.
Keep in mind that it takes blue and yellow to make the color green. In many reptile species, the yellow pigment is slow to develop, making the young of the species look blue. If you have ever seen photos of the green tree boas, the new borns are bright, vivid blue...while the adults are green. This same delay in yellow pigment development is what is happening to the "blue" hatchlings that turn green.
The dewlap will be somewhat mottled green and white, with a little black or brown. There are usually small white "epaulettes" on the shoulders, which may or may not be rimmed with blue. Some of the small raised and flat scales on the neck may be blue or white.
As the iguana heads into the start of its second year, the baby colors will have started to mutate into their adult colors. Depending on where they are from, they may lose their bright deep green, fading to a lighter green. Belly bands, in males especially, become more vivid as sexual maturity is reached at about eighteen months of age.
While a snake, who sheds its skin in one piece, will turn milky a few days before the actual shed, iguanas will develop milky white patches. The snout, one hand, a stripe along both sides of the dorsal crest, the ribs...almost as if someone has painted them with a transparent white paint. These are the areas that are getting ready to shed. Once the old (top layer) of skin is ready to come off, the layer will start to separate over these patches. As some of these older patches of skin is in the process of shedding, other patches will appear as other areas get ready to shed. For further information on shedding, please read the article on Skin Shedding.
Some iguanas who have been at suboptimum temperatures for a while will develop lines and squiggles on their face, head and/or body that look like someone has been doodling on them with a blue ball-point pen. This is a good indication that you need to get your iguana warmed up. It may take an hour or two at proper basking temperatures for the doodle marks to fade away.
Females who change colors may develop a gentle wash of rust, including around the eyes. I have found that the females who are the most intensely orange and remain orange for long periods of time are generally those who dominate their households, similar to the way a dominant male will retain some orange or rust throughout the year.. Once they move to a household where they are no longer alpha (to humans), they lose much or all of the orange.
The stress may be due to several factors - environmental, psychosocial, and physiological. Stress in one area, such as an improper photoperiod, an aggressive cagemate, a hovering cat, or poor diet, will lead in time to physiological problems as the immune system becomes compromised and system infection sets in. Other articles, such as Signs of Illness and Stress in Reptiles, Housing Multiple Iguanas: Issues and Concerns, Iguanas and Other Family Pets, and Iguanas and Change-Related Stress all discuss other signs of stress and some causes of environmental and psychosocial stress in iguanas. Other articles which touch upon environmental stress include Reptile Housing: Size, Dimension, and Lifestyle, Basic Cage Design Problems, and Lighting and Heating.
Graying/Browning is a sure sign that the iguana is not happy or healthy and that something needs to be done to rectify the situation. In some cases, it may mean placing the iguana in a new room (or home) where it will not be subjected to other animal, iguana, or human stressors. In other cases, the iguana will improve once the environmental conditions improve.
All such iguanas should be checked by a reptile vet. Prolonged stress hampers immune functioning, and these iguanas easily get sick; mouth rot (stomatitis) and abscesses are common in highly or chronically stressed iguanas. Natural internal parasite and bacterial populations that otherwise do not cause any problems may explode, causing illness and increasing stress levels. These animal may require antibiotics and may require rehydration through injections of fluids.
Monitoring your iguana's skin coloring, as well as appetite, feces, and behavior, are all ways to assess its health and well-being. Use it to your advantage!
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