Although they do not have the same colorizing capabilities as Panther Chameleons, Veiled Chameleons do change color. This unique transformation makes them a favorite exotic pet but watch out! Their color changes could be telling you something.
How does their Environment affect their Adaptations?
Chamaeleo calyptratus is indigenous to the middle east, mainly Yemen and Saudi Arabia. Unlike the tropical New World species of chameleon, the Veiled does not have the same kind of colorful backdrop. They are arboreal, meaning they live in trees, and so the base color of the Veiled Chameleon is between green and brown.
The Veiled’s prehensile tail helps them to move about on precarious tree branches. They anchor their tail around their perch and reach very slowly towards the next branch. Their feet technically have five digits like our own, but theirs have evolved to grip branches, so they look a lot more like bird feet or oven mitts.
The mountain ranges they inhabit provide them with plenty of insects to eat. They use their spring-loaded tongue to capture prey, like grasshoppers and butterflies. They use their independently moving eyes to track prey and predators. Because they are such a slow-moving animal, they prefer to remain still when predators are nearby, rather than run away.
In the wild, they do use their color for camouflage, but mainly its function is to absorb light and heat, and also to showcase their moods. We’ll discuss how to tell if your Veiled Chameleon is stressed out or excited. But first, let’s look at the mechanisms at play for their extraordinary transmutation.
How do Veiled Chameleons change color?
It’s in their skin cells:
All reptiles have two kinds of specialized color-capturing skin cells, melanocytes, and chromatophores. Melanocytes, located in the epidermis, the upper layer of skin, contain melanin. That’s the same black pigment that humans and other species use to create shades of color.
Melanocytes on the surface of a reptile’s skin maintain an almost constant pigment though. Only when the reptile sheds do they transfer this melanin to the next layer of melanocytes. That’s why reptiles appear lighter in color when they shed.
Chromatophores, on the other hand, are located deeper in the dermis layer. The unique color of a Veiled Chameleon depends on three types of chromatophores: xanthophores, melanophores, and iridophores.
Xanthophores contain yellow to reddish pigments and they are not as involved in the color change process. The pigments in xanthophores are static and they are derived from the chameleon’s genetics and their diet.
Changing Patterns
Similar to melanocytes, melanophores carry the black pigment, melanin. However, melanophores can actually transfer melanin across their surface. The unique star shape of a melanophore cell is the key to its color change.
When these cells move melanin from their center, out to the arms of the star, then the hue changes from dark to light. Picture a sea star using its suction cups to move particles of sand across its body.
Melanophores are interspersed between xanthophores and they create the patterns we see on a Veiled’s skin. Scientists used to believe that melanophores were specifically responsible for chameleon color change. However, researchers now recognize that the iridophores are at the heart of this ability.
Crystal Magic
Iridophores like their name suggests, contain iridescent, but otherwise colorless nanocrystals. These microscopic reflective crystals can be stacked on top of each other within the cell to create white to bluish hues, as well as ultraviolet color. Because iridophores are located underneath the other chromatophores, they affect the hue of the cells above them. It’s kind of like looking through stained glass.
Why ultraviolet?
Infrared and ultraviolet waves are incredibly important to cold-blooded animals like chameleons because they need a wide spectrum of light to metabolize their food. Veiled Chameleons live in dynamic environments, and they need to maintain their body temperature throughout the changing climate. By being able to change their skin color, chameleons can absorb or reflect more light.
Unlike us, chameleons can also see ultraviolet light, so it’s no surprise that they use it to communicate with other members of their species. Other reptiles, birds, and insects are known to see ultraviolet light and it is fascinating to watch how the changes that we don’t even notice can add subtle nuance to their display.
Why do Chameleons change color?
Heat and Light
Unlike mammals, who create heat when they digest food, reptiles need to absorb heat from their environment and use it to break down nutrients. Cold-blooded animals have very slow metabolisms, which means they can go a lot longer than we can without food.
Part of the reason chameleons moves so slowly is to conserve their energy. When they are warm, they may appear more agile and interested in their surroundings. When they are cold, they will hardly move a muscle.
A Veiled Chameleon in the cold will darken its colors to absorb more light. In the late evening and early morning, your chameleon will look darker, duller, and more brownish. In the middle of the day, they will warm up and appear lighter and brighter, and possibly more greenish, because they want to reflect away some of that light.
Interestingly, you can actually hold a light to one side of a chameleon and only that side will brighten. This means their body can control which chromatophores are stimulated at any given point. There are other species of lizards, like the Bearded Dragon and the Anole, who can change their color, but they don’t have that same control.
Communication
In much the same way that Bearded Dragons will blacken their chines and King Cobras will expand their hoods, chameleons use their color to attract mates and defend territory. However, not all chameleons can change their color. Pigmy chameleons, the smallest of the species, do not change much at all. Instead, they stay brown to camouflage themselves.
Other species like the Panther Chameleon, have a much wider range of color because of the number of iridophores in their skin. Similarly, mature male Veiled Chameleons will actually appear brighter than females or juveniles because they have thousands of more iridophore cells.
What are they telling you?
When Veiled is relaxed, their colors will be muted and plain. They may be darker or lighter, depending on the temperature, but they won’t be trying to stand out at all and they may seem to blend into their surroundings. The chameleon will have a neutral body position, without any puffing out or flattening. They will move unhurriedly in their enclosure, either slowly looking for food, or exploring.
When they are feeling threatened or ill, they will darken their color rapidly. They will also curl up into a defensive position and stay very still. Even after the threat has passed, the chameleon will continue to play possum. Veiled Chameleons are known to be sensitive pets, so over-handling them, especially when they are afraid can lead to stress and even early death.
An excited or stimulated male Veiled Chameleon will quickly brighten their colors. If they were forest green a moment ago and then they shot into lime green with blue patterning, they may have just seen a potential mate or a potential rival. While we like to see them at their brightest, take care that you are not the one they are acting territorial around.
Female Veiled Chameleons will also change color to let the male know they are ready to mate. A receptive female will be emerald green with blue blotches, but an unreceptive one will darken her colors and flatten her body in agitation when the male approaches. After a female has bred, she will turn blackish-green with light blue spotting.
What are the signs that something is wrong?
If your chameleon isn’t eating or pooping, or if they are constantly dark, lethargic, and defensive, then you need to take them to a reptile veterinarian. Female chameleons can become egg bound, so be aware of your female hasn’t lain a brood during her season.
Also, watch for injury to the skin. Because of the way their skin cells renew, reptiles take much longer to heal than mammals. Plus, chameleons have thin skin, not at all like the scales of other reptiles. Infections can be fatal, so if you see discoloration, swelling, or leakage around an injury, take your chameleon to the vet.
How can We Communicate with Them?
You should take care to be slow-moving and quiet around your Veiled. Try not to enter their space at all, unless you’re feeding them or cleaning their cage. Do not handle them unless it is necessary to do so. If they puff up their bodies and open their mouths, it is their way of saying they are going to bite you.
Although they are beautiful, Veiled Chameleons are NOT a cuddly pet like a Bearded Dragon or Uromastyx. They are, however, extraordinary reptiles that can teach us a lot about body language and the importance of communication. Pay attention to what your Veiled is telling you, and enjoy them for their beauty rather than their company.
References:
https://phys.org/news/2013-05-chameleons-creatures-colour.html
http://www.anapsid.org/basicdermatology.html
https://animals.mom.com/identifying-veiled-chameleons-color-mood-5721.html
https://www.reptilesmagazine.com/how-to-breed-veiled-chameleons/
