Answered by Alana Jensen, INL ESER Program www.idahoeser.com
If you’ve seen cartoons where chameleons can seemingly change to almost any color to match their environment, you may be disappointed to learn that the truth is quite different. Many species can’t even change to a color other than different shades of gray, green, and brown.
Chameleons are really defenseless. They don’t have venom, their skin isn’t poisonous, and they’re not fast moving. Staying hidden is really their only tactic to evade predators. Luckily, for chameleons to camouflage, it doesn’t require color change at all. In their natural state, they already look a lot like leaves or branches, much like stick insects looks like sticks.
But chameleons do have the ability to adjust how bright their skin appears. When there’s less light, such as on a tree deep inside a forest, brown to black pigment cells called melanin flood to the skin’s surface and cause the chameleon to appear darker, and thus more camouflaged.
In other words, chameleons can, in fact, change the color of their skin to match the environment, but within a narrow sliver on the color wheel.
Some chameleons can turn almost every color, but these more elaborate displays are saved for another purpose than camouflage. Chameleons are highly territorial. When two males encounter each other, there’s a fierce show-off of color. The weaker male, who’s often smaller and more dimly colored, will concede defeat by turning off his display first, which indicates that he doesn’t want to fight.
Chameleons will also use their displays to dazzle females during courtship.
Some scientists believe that changing color may also help chameleons regulate their body temperature. Chameleons are ectotherms and so they can’t retain heat generated from their metabolism. Instead, they have to warm up using the sun. Darker colors absorb more light, so when it’s cold and the sun is up, they wash themselves with melanin to darken and thus accelerate warming.
How Do Chameleons Change Color?
Chameleons are born with special cells that have a color or pigment in them. These cells lie in layers under the chameleon’s outer skin. They are called chromatophores. The top layers of chromatophores have red or yellow pigment. The lower layers have blue or white pigment. When these pigment cells change, the chameleon’s skin color changes. These changes can occur in as little as 20 seconds.
Chromatophores change because they get a message from the brain. The message tells the cells to enlarge or to shrink. These actions cause cell pigments to mix, just like paint. A chemical called melanin also helps chameleons turn color. Melanin fibers can spread like spiderwebs through layers of pigment cells and their presence causes skin to darken.
Tints and Shades
To appear darker, a chameleon will change his shade. In color theory, a shade is a mixture of a color with black, which increases darkness, while a tint is a mixture with white, which decreases darkness.
Materials: white paper, paint in any color choice, white paint and black paint , brushes, water
- Turn the paper sideways to create the background first. Fold paper in half and open so you have a vertical line.
- Brush one stroke of the solid color (red in the example) on the fold line.
- Mixing white with a color makes it lighter. This is called a tint. Mix a bit of white in your red and do another stroke on the left side of your first stroke.
- Add a bit more white, and continue tinting each stroke a little more.
- Mix the original color with a TINY bit of black. Remember, a little black goes a long way.
- Keep adding black a bit at a time to add shade to your painting.
- When you’re finished with the background, paint a foreground silhouette in black.