Chameleons certainly can bite the hand that feeds them, but because you should not directly touch your chameleon unless necessary, they rarely have the opportunity to do so. Biting is often the last resort of stressed or frightened chameleons, as most would prefer to avoid altercations by fleeing or dissuading perceived threats with bluffs. While chameleons have teeth and surprisingly strong jaws for such fragile-looking animals, their bites do not usually cause serious wounds and are only a minor annoyance for keepers.
Some chameleon species exhibit more aggressive tendencies than others do. For example, many veiled chameleons (Chamaeleo calyptratus) do not tolerate much interaction with their owners. If sufficiently aroused, they may attempt to bite.
In general, small chameleon species are incapable of generating significant force with their mouths, so even if they do bite, it is a nonissue. By contrast, large species, such as panther (Furcifer pardalis), Malagasy giant (Furcifer oustaleti) and Parson's chameleons (Calumma parsonii), may be able to apply an appreciable amount of force, enabling them to break the skin or deliver a strong pinch.
While their bites may keep human keepers cautious, they are hardly sufficient to discourage a hungry predator. Accordingly, chameleons have had to evolve more effective means of protecting themselves. In many respects, these defenses mirror those of most other lizards and include techniques such as crypsis, fleeing and bluffing.
Contrary to popular perception, chameleons do not change colors to blend in with their environments. Instead, most species are typically clad in cryptic colors and change colors only when thermoregulating or interacting with other animals. In some cases, these bold colors are intended as a threat, and chameleons display them while simultaneously flattening their bodies and gaping their mouths.
While aggressive snakes, monitor lizards and iguanas are often challenging to move, manipulate or handle, chameleons rarely present such difficulties. Tame chameleons rarely object to their owner's presence, and those inclined to bite generally act in aggressive ways, rather than simply biting suddenly.
When you have to move your chameleon, remove the entire perch to which he is clinging rather than try to remove him from his perch. If he is tame and appears calm in your presence, you can allow him to crawl onto your hand or arm, but this is not advisable with a specimen displaying signs of stress or aggression. If you must restrain the lizard, it is best to grab his body behind the head, which will prevent him from turning and biting.