By Dr. Becker
Chameleons have many features worthy of note. Their sticky tongues, which extend out longer than their bodies, can snatch an insect in the blink of an eye. Their tails act as a “fifth hand” allowing it impressive dexterity even when hanging on to a branch by tail alone.
Its eyes are similarly impressive, rotating nearly 180 degrees without moving its head, and each eye moves independently of the other. However, the one feature that has brought the chameleon the most attention is its ability to change color rapidly in response to its environment.
A chameleon’s changing skin color isn’t done to blend in with its background, as was once commonly believed. Instead, it’s thought chameleons change color in response to physiological cues.
A chameleon’s color is more likely a form of communication that depends on light intensity, temperature, and emotional state, used to express things such as courtship status, competition, and stress.1,2
The chameleons’ changing colors were recently used to help determine diversity among Madagascar’s panther chameleon, and what was believed to have been a single species turned out to be at least 11.
11 Separate Species of Chameleon Discovered
Scientists took photographs and blood samples from 324 panther chameleons in Madagascar, where they are known to live in separate groups. They then analyzed the DNA in a laboratory.
Not only was the DNA determined to be from distinct lineages with “very low interbreeding between other populations,” but subtle differences in color and pattern turned out to reveal which species the chameleons belong to.3
The study suggests there is much hidden biodiversity left to be discovered in Madagascar, a country where up to 90 percent of its species exist nowhere else on the planet.
It’s thought that only 16 percent of the 12 million species on earth have been discovered, but many newly discovered species, including some panther chameleons, may already be endangered.4 As reported by the Christian Science Monitor:5
“… [In Madagascar] widespread deforestation for firewood and charcoal production threaten 400 species of reptile, 300 species of amphibians, 300 species of birds, 15,000 species of plants, and countless species of invertebrates… species are going extinct faster than nature is creating them.
‘We now know for certain how much faster species are going extinct,’ said Stuart Pimm, a conservation ecologist at Duke University and president of the nonprofit conservation group Saving Species.
As an example, Pimm told LiveScience that the planet should lose about one bird species every 1,000 years, but with human activities, at least 150 species of birds have gone extinct in the last 500 years.”
Chameleons Change Color Using Built-In Crystals
In case you’re wondering how chameleons carry out their seemingly magical color-changing feat, it’s made possible by crystal-containing cells in two layers of their skin.6 The photonic crystals are also responsible for creating shimmer on butterfly wings, fish scales, feathers, and more.
In chameleons, the double layer of crystal-containing cells allows the animals to have efficient camouflage, protection from sunlight as well as put on flashy displays for mating. According to National Geographic:7
“Only adult male panther chameleons… have a fully developed upper layer of the cells, called iridophores, which they use to put on multihued shows for mating. When the crystals are close together, such as when the animal is relaxed, they reflect blue light.
When they are combined with yellow pigments in the chameleon skin, the animal appears green. Stretching the cells and moving the crystals farther apart produces colors ranging from yellow to red.
All of the chameleons have a deeper layer of iridophores that reflects a broader spectrum of light, particularly the near-infrared, which is invisible but is close to the wavelengths felt as heat.
Scientists speculate that these deeper crystal-containing cells help the cold-blooded animals regulate their body temperature, while the more superficial layer of color-changing cells is involved in camouflage and flashy mating displays.”
See Chameleons in Action…
The National Geographic video above shows chameleons in the wild, giving you a glimpse of these beautiful creatures in their native habitat. Their striking colors have made them popular for the pet trade, however, and large numbers of wild chameleons are collected for this purpose.
If demand increases, this practice could put local populations at risk, so if you’re considering a chameleon as a pet, be sure to source one from captive-bred stock or a rescue organization.