Does anyone know how they go about changing colors? And if a chameleon can change colors, how come a leopard can’t change its spots?
According to this article in Encarta:
And What makes a chameleon change color by Tim Susman, Staff Zoology, University of Minnesota, St. Paul, MN says:
I would guess that other animals (including leopards) cannot change color(s) because they have neither the cells that redistribute pigment nor the hormones that trigger those cells.
Many lizards — and even other animals, like cuttlefish — can change color. They usually do use chromatophores.
Chromatophores do not, in and of themselves, cause color change; many fish contain chromatophores and yet cannot change color. In animals like cuttlefish, the chromatophores contract or expand. IIRC, this is via the contraction or relaxation of a muscular ring surrounding the chromatophores. It’s the same as how your iris contracts to enlargen the pupil, execpt the “pupil” (chromatophores) are colored and the “iris” is not. The chromatophores come in different colors and the relative combination of the base colors causes them to mix, like an RGB monitor.
Also, birds and mammals cannot change color over their entire body like a chameleon because their epidermis, or uppermost skin layer, is not visible.
By the way, birds and mammals can change color, but this is usually by altering bloodflow — humans and caracaras blushing are classic examples.
Thank you Kat and Thrush for the info, but actually I wasn’t serious about the leopard thing. It was my small(read “lame”) attempt at humor.