Chameleons - magic animals :)
2009-12-14 @ 21:22:32
Chameleons are a distinctive and highly specialized clade of lizards. They are distinguished by their parrot-like zygodactylous feet, their separately mobile and stereoscopic eyes, their very long, highly modified, and rapidly extrudable tongues, their swaying gait, and the possession by many of a prehensile tail, crests or horns on their distinctively shaped heads, and the ability of some to change color. Uniquely adapted for climbing and visual hunting, the approximately 160 species of chameleon range from Africa, Madagascar, Spain and Portugal, across south Asia, to Sri Lanka, have been introduced to Hawaii and California, and are found in warm habitats that vary from rain forest to desert conditions.
Some chameleon species are able to change their skin colors. Different chameleon species are able to change different colors which can include pink, blue, red, orange, green, black, brown,light blue yellow and turquoise.
Some varieties of chameleon - such as the Smith's dwarf chameleon - use their color-changing ability to blend in with their surroundings, as an effective form of camouflage.
Color change is also used as an expression of the physiological condition of the lizard, and as a social indicator to other chameleons. Some research suggests that social signaling was the primary driving force behind the evolution of color change, and that camouflage evolved as a secondary concern.
Chameleons have specialized cells, collectively called chromatophores, that lie in layers under their transparent outer skin. The cells in the upper layer, called xanthophores and erythrophores, contain yellow and red pigments respectively. Below these is another layer of cells called iridophores or guanophores, and they contain the colorless crystalline substance guanine. These reflect, among others, the blue part of incident light. If the upper layer of itchromatophores appears mainly yellow, the reflected light becomes green (blue plus yellow).
Some chameleon species are able to change their skin colors. Different chameleon species are able to change different colors which can include pink, blue, red, orange, green, black, brown,light blue yellow and turquoise.
Some varieties of chameleon - such as the Smith's dwarf chameleon - use their color-changing ability to blend in with their surroundings, as an effective form of camouflage.
Color change is also used as an expression of the physiological condition of the lizard, and as a social indicator to other chameleons. Some research suggests that social signaling was the primary driving force behind the evolution of color change, and that camouflage evolved as a secondary concern.
Chameleons have specialized cells, collectively called chromatophores, that lie in layers under their transparent outer skin. The cells in the upper layer, called xanthophores and erythrophores, contain yellow and red pigments respectively. Below these is another layer of cells called iridophores or guanophores, and they contain the colorless crystalline substance guanine. These reflect, among others, the blue part of incident light. If the upper layer of itchromatophores appears mainly yellow, the reflected light becomes green (blue plus yellow).