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One common question that iguana owners ask has to do with the color of their iguana. People wonder what is “normal” coloring and what is not. Various products in the pet stores claim to enhance your iguana’s coloring. Some iguanas are sold under special names at a higher price because of different coloring they have. Sometimes color changes are seen but the cause is not apparent, thus causing the owner to worry about his/her iguana. Conflicting or incomplete information can be confusing.

One important thing to realize is that although Iguana iguana is commonly called the “green iguana”, not all members of this species are green. Healthy baby iguanas tend to be bright green or greenish-blue in coloring. However, as they age, most iguanas lose this bright coloring and end up with a duller green/gray/brown or even orange coloring with brown or black markings. This is completely normal and should be expected. Even the so-called "Blue Diamond" iguanas (sold in pet stores under the Fluker brand name) will eventually lose some of their bright baby coloration. Coloring in adult iguanas varies according to their country of origin. According to Melissa Kaplan, author of Iguanas for Dummies, iguanas from Mexico tend to show brownish-orange coloring in males on the legs, while the body remains green. Iguanas from Central America are often pale green, with light blue/white heads and bold black or brown belly stripes. Mature adults often display some orange coloring all year, especially in males. South American iguanas often retain blue coloration. Since all baby iguanas share the same bright green coloring, it is always a surprise what you’ll end up with once your iguana matures.

This iguana was black and white with no green coloring at all - a highly unusual mutation. Please note: Loss or lack of color like this may also be a sign of illness.

It is a commonly held belief that green iguanas can change color like chameleons can. However, this is not accurate. Iguanas are capable of color changes, but only in specific situations. Some situations deal with stress, others with breeding issues, and some simply because the iguana is basking in the sun.

One of the most obvious color changes in the iguana is when it is taken outside for some real sunlight. Most iguanas immediately become dark. Their heads turn dark grey, almost black for some individuals, and the stripes on the iguana’s body become very apparent. Many iguanas have brown marks that appear on their back that are never seen inside, and give the iguana a sort of leopard-like markings. The reason they darken is because dark colors absorb more of the sun than light colors do. It’s like wearing a black t-shirt on a very hot day compared to wearing a white t-shirt. The white t-shirt reflects the light better, the black t-shirt absorbs it more. You also feel much hotter in the black t-shirt. When the iguanas start to feel too hot, they lighten up their coloration. This helps them thermoregulate when they are in the sun.

Below, Jose shows color change that is typical of basking iguanas. The photo on the left shows her normal coloring indoors, while the photo on the right illustrates the darkening of color in the sun.

Lightening of color is common in iguanas that are too hot. The photo below shows Gil panting in the sun, with his head an almost white color to reflect the heat.

An iguana that is indoors and is too cold may also have a dark-grayish coloration. As explained above, this is an attempt to absorb more heat from the environment. If the temperature of the iguana’s environment is raised to appropriate levels, the color will again lighten. The types of lights used in an iguana’s enclosure may also affect its coloring. Different types of lights reflect differently off the iguana’s skin and can enhance or change the appearance of the iguana’s color while they sit under the bulbs. Some lights, such as mercury vapor bulbs, have a reputation for actually causing an iguana’s skin pigment to brighten so that its color is enhanced even when it is not directly under the light. Reports of this effect vary.

Stress can produce a colorful array of shades that you would never normally see on an iguana. Each iguana responds in its own way regarding color changes due to stress. An iguana belonging to one of the GIS Team members lightens the color on her head until it is a pale grey, and blue-green spots occur in various areas on her head. The color on her body turns a bright yellow-green, which obliterates the normal bits of bright blue that she has on her body. Once the source of stress is gone (usually a trip to the veterinarian), she slowly returns to her normal colors. A second iguana belonging to another GIS Team member exhibits a color change that turns her head bright white when she is stressed and/or afraid. In yet a third iguana owned by a GIS Team member, stress produces a very dark, almost black coloration on the head and a darkening of the body. Owners should learn to recognize their iguana's stress colors.

Here is Jose wearing her stressed colors. Notice the increase in brown and yellow shades, compared to her normal coloring when she is relaxed (above left).

Notice the increase in brown coloring and the darkness of stripes when Lew is upset (left) compared to when he is relaxed (right).

Breeding season produces many color changes in both male and female iguanas. The most notable one is the orange color that males develop as they enter their season. It generally starts on the legs, and the shade of orange can actually vary from a light orange to a very bright, almost neon orange. The color can also change on the sides of the iguana’s body, as well as the tail. The coloration can last for a few months, as that is the normal length of iguana breeding season. Females may also develop some orange coloration, but rarely to the extent that males do. Generally the color fades as the iguana’s breeding season ends, but some iguanas retain the coloration and always have some orange on them. This is more common in males.

Below are photos of two mature males in breeding colors. Max (left) shows a typical amount of orange coloring on his legs. Iggy (right) illustrates the full-bodied, bright orange that some males develop.

The worst color change an iguana can have is when it is sick. Generally, when you go to the pet store and you look at the iguanas, you can spot the sick ones right away. They tend to be brownish in color, and show other signs of illness such as lethargy. Your own iguana can get that brownish color if it gets sick enough before you take it to the veterinarian. A well-cared-for iguana that is slightly sick may simply appear not as vibrantly colored as normal. Although orange hues are normal for some iguanas, they are sometimes a sign of severe dehydration or kidney disease. If orange coloring appears suddenly in an older iguana and is not associated with breeding season, a veterinary visit is recommended.

This poor little guy is Peewee. Peewee was in terrible shape when he was rescued. In addition to thermal burns (the black marks on his back) he was also afflicted with a fungal skin infection, internal parasites, and a severe eye infection. Thankfully, Peewee is now receiving treatment and proper care, but his yellow/brown coloring in this photo clearly indicates how ill he was.

Because each iguana is different from others, it is important that owners become aware of what is normal for their iguana and what is not. Recognizing stress colors can help owners better understand their iguana's moods and needs. Any sudden change in color that is not associated with any of the above situations (maturity, stress or breeding season) can indicate illness and should be checked out by a veterinarian.

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