Like other chameleons, the graceful chameleon (Chamaeleo gracilis) has a number of odd traits: bulging eyes that move independently, fused toes that work like pincers, a tongue that can shoot out like an arrow, and a helmet-shaped head. The chameleon’s ability to rapidly change color, though, is its most famous trait.

For a long time, people thought that chameleons changed colors to blend in with whatever they touched. Scientists now believe they change color primarily to communicate. They change hues during courtship, when defending territory, and when under environmental stress.

In their home in sub-Saharan Africa, graceful chameleons can be a range of greens, browns, and yellows. But how do they change hues so fast? 

In their skin, chameleons have tiny, nanoscale crystals under a layer of pigmentary skin cells. They can change the spacing of those crystals by stretching or relaxing, which affects how the crystals reflect light.

When the chameleon is relaxed, the crystals are close together and reflect more blue light. Combined with the yellow pigments in the lizard’s skin, the chameleon looks green. When the crystals move further apart, they produce colors ranging from yellow to red. 

Graceful chameleons are plentiful and live in a wide range of habitats, from dry to humid mature forests and in savannas. About 31 centimeters (12 inches) long, they are one of the four most popular chameleons exported for the pet trade. Valued in traditional medicine, many of these chameleons are also captured, killed, and dried for medicinal purposes.

Despite these pressures, as well as habitat loss, the graceful chameleon has a stable population and is plentiful in areas with suitable habitat.

  1. Do any other animals have the kind of crystals chameleons do?

    • Answer

      Chameleons have a matrix of crystal structures—called photonic crystals—that reflect light. The colorful shimmer of butterfly wings, beetles, fish scales, and feathers comes from these same light-reflecting crystals. Octopus, cuttlefish, and squid, all masters of underwater camouflage, also depend on photonic crystals for their color changes.

  2. How does the graceful chameleon spend its day?

    • Answer

      Although the graceful chameleon is arboreal, it is frequently found on the ground in villages or on paths. Diurnal, the chameleon is active in the early mornings hunting for prey and basking in the sun. During the midday heat, it rests in the shade, hiding from predators (such as birds and snakes) among tree leaves. In the afternoon, as temperatures cool, it becomes active again, hunting until dusk. At night, it rests in low branches.

  3. Why do chameleons change color?

    • Answer

      People used to think chameleons changed color purely for camouflage, blending in to match whatever they touched. Scientists now believe chameleons primarily change color to communicate. Males and females change color to express whether they are interested in mating or not. Males change color when facing other males to defend their territory. (They also arch their backs, raise their tails, and expand their neck pouches to look bigger.) Researchers are still working to understand all of the chameleon’s mysteries, though.

  4. Can chameleons see well?

    • Answer

      Chameleons have excellent vision. Their bulging eyes move independently, focus rapidly, and can zoom in to see an object better, much like a telephoto lens.

  5. Are many graceful chameleons sold in the pet trade?

    • Answer

      Graceful chameleons are one of the four most popular chameleons sold in the pet trade. Estimates suggest 45,000 of them were exported between 1977 and 2001. Demand for them comes mostly from the United States. It’s unclear how these sales will impact their population over the long term. For now, they are stable and quite plentiful in their natural habitat.

  6. How does a graceful chameleon capture its prey?

    • Answer

      To capture grasshoppers, wasps, cicadas, and other insects and arthropods in its diet, the graceful chameleon shoots out its long, slender tongue, much like an arrow being shot from a bow. Sticky mucus on the end of its tongue helps capture the prey, as does a vacuum created by muscles at the tongue’s tip. The tongue is then rapidly retracted into the chameleon’s mouth. Other lizards use their tongues to capture prey, but chameleons can propel their tongues much farther—typically a distance more than twice their body length.

courtship
Noun

behavior in animals resulting in mating.

Noun

environment where an organism lives throughout the year or for shorter periods of time.

hue
Noun

tint or general variety of color.

nanoscale
Noun

length scale whose relevant unit of measurement is the nanometer (nm), or a billionth of a meter. Also called the nanoscopic scale.

pigment
Noun

material that changes the color of reflected or transmitted light.

pincer
Noun

grasping appendage or apparatus.

population
Noun

total number of people or organisms in a particular area.

savanna
Noun

type of tropical grassland with scattered trees.

territory
Noun

land an animal, human, or government protects from intruders.

trait
Noun

characteristic or aspect.