Chameleons are able to change the color of their skin and to blend into their environment, but not only. The color change of chameleons is controlled by the nervous system. As most reptiles, they are ectothermic, their body temperature depends on their environment's conditions. In response to heat stimuli, they are able to change color for thermoregulation. Their color also changes according to mood, to reproductive state, to health or even to stress conditions.