Melissa
Kaplan's
Herp Care Collection
Last updated
January 1, 2014
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.
Iguana
Color Variants
The following
color variants (except the brown) are not generally seen until the iguana
is heading into sexual maturity. The hatchlings' deep greens, useful in
camouflaging them, begins to lighten, striping or patching diffuse or
develop, as they reach one year of age.
Brown
Iguanas
The exceptions that I have seen are individuals who are predominately
brown, tan and cream colored. Their markings and shadings are just like
other iguanas, just the colors are different. When happy/healthy, they
may get some green in their stripes or markings. They essentially look
like a photograph negative of a green iguana. This color variation should
not be confused with iguanas who have turned brown due to stress.
Blue
Iguanas
There is one (or maybe more) area within the iguana range that produce
predominantly blue iguanas. These iguanas, when happy, exhibit a beautiful
turquoise blue color. When they are cold or stressed, they are green.
The irises of their eyes tend to be a deep reddish-brown, and they generally
have black skin surrounding the scales on their bodies, heads, tails and
dewlaps. Some may have lots of black in their eyelids.
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.
Gray
Heads
Some iguanas, mainly those from some areas in Central America, have
very gray, scaly looking heads and necks when they are mature. Their rostrums
may be equipped with tiny horns or very pronounced knobs, and their bodies
tend to be quite dark green. Many have stripes that are more blurred,
or reticulated skin patterns. During breeding season, the heads and bodies
of males can become covered with a rusty-colored wash, turning to deep,
bright orange when they are excited (during courting and territorial displays).
White
Heads
Iguanas from Columbia tend to have very, very, pale green heads.
People who see them from a distance or don't look very carefully often
think that their heads are white. When aroused sexually or territorially,
the head color will change within seconds to a pale baby blue.
Red
Heads
The iguanas from one area in South America whose heads are normally
colored red.
Color
Changes
When you get
a baby iguana, it is usually a deep, bright vivid green with some body
stripes, and bands around the tail that may or may not meet evenly. The
stripes on the body and tail are deep, chocolatey brown. Some iguanas,
have less body striping, instead having faint bronze patches that get
more visible and deeper in color when they have been basking for a while.
Others have a more reticulated patterning, almost like you are seeing
them through military camouflage netting, with this reticulation becoming
stronger as they reach maturity..
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.
Pre-Shed
In the weeks prior to the actual shed (which, in a healthy iguana,
will occur every 4-6 weeks, except during the slower winter growth period),
you will start to see some skin color changes. The normal color will start
to dim or get dull, even yellowy (note: this is not the bright squash
yellow associated with long-term stress color changes). Peruvian blue
iguanas will turn green, then yellowy.
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.
Thermal
Changes
The iguana's normal coloring is affected by heat and cold. If too
cool, it will be come very dark: dark colors absorb heat and so this change
will help the iguana absorb more environmental heat. If too hot, it will
become very light in color (within its individualized color range).
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.
Breeding
Season
Most males, and the females of some populations, change color during
breeding season. The skin may develop a wash of rusty orange across the
entire body, or a paling of the green with bold, deep, bright orange appearing
on the dewlap, spikes, body and legs. The color change occurs several
months before actually breeding occurs, and may last for several months
after the male's usual breeding season ends if there are females around
who are still in season. Some males and females will retain some breeding
color all year, especially if they are dominant to other iguanas - or
humans - in their environment.
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.
Signs
of Stress
Overall dark
gray, dark brown, black, and yellow are not normal iguana colors. While
there are exceptions to this rule (see Brown and Gray Headed above), the
exceptions are rare. Generally speaking, when an iguana is stressed, the
color change begins on the head, upper body, tail, legs, spreading around
the torso to the belly. The belly may remain green or yellow for some
time after the rest of the body has grayed or browned out.
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.
Any of the health problems discussed in the health section on the Iguana Care page and on the Herp Health page may cause color changes.
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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