Because of the circulation of the blood of the reptile, in increased temperature, either of the ambient air or of its own body, producing all the variations of the skin. As the passions of the human mind change the colour of the skin, as well as the form of the features, and according to the rapidity of the flow of blood; so the feelings of the chameleon may also, in some measure, produce analogous changes in the reflecting surface of the skin. - J. Murray, F.L.S.
The reflection of coloured objects on the glittering scales of the chameleon, probably gave origin to the fable that its colour is regulated by that of the bodies near which it is placed. - Notes to Blumenbach.
Whatever may be the cause, the fact seems to be certain, that the chameleon has an antipathy to things of a black colour. One, which Forbes kept, uniformly avoided a black board which was hung up in the chamber; and, what is most remarkable, when it was forcibly brought before the black board, it trembled violently, and assumed a black colour.
It may be something of the same kind which makes bulls and turkeycocks dislike the colour of scarlet, a fact of which there can be no doubt. - J. Rennie.
Because its lungs are very large, and by expanding them, the animal can, at pleasure, make itself appear large or small.
Because they can be directed in different ways; for instance, one upwards and the other backwards; and that with great rapidity.
* See the Woodpecker, page 102.
Because the chameleon's tongue is contained in a sheath at the lower part of the mouth, and has its extremity covered with a glutinous secretion: it admits of being projected to the length of 6 inches, and is used in this manner by the animal in catching its food, which consists of flies, etc. It is darted from the mouth with wonderful celerity and precision, and the secretion on its extremity entangles the small animals which constitute the food of the chameleon.
The form of the chameleon's tongue is, however, very different from that of the woodpecker. - Notes to Blu-menbach.