| MadSci Network: Zoology |
Chameleons change color for a variety of reasons. Cells called chromatophores in their skin redistribute pigment to cause the color change. The chromatophores are triggered by hormones, which can be sent out in a variety of circumstances. Temperature can trigger a color change (in fact, chameleons can regulate their body temperature by changing color -- darker colors will absorb heat, lighter colors will reflect it). Chameleons will often change color when they move from one color environment to another (as from the leaf of a tree to its bark). The mental state of the animal can affect its color as well. If a chameleon is agitated, it may well change color.
Two pages that would be good starting points to learn more about chameleons are: http://www.skypoint.com/members/mikefry/chams2.html and http://www.concentric.net/~Mglavin/library.html. The first has lots of information and a few pictures, and some further links. The second has a listing of some books that you might be able to find at a local library.