Alternative meanings: Chameleon (computing), Chamaeleon

Chameleons (family Chamaeleonidae) are small to mid-size reptiles that belong to one of the best known lizard families. They are famous for their ability to change their colour also because of their elongated tongue and their eyes which can be moved independently of each other. The name "Chameleon" means "earth lion" and is derived from the Greek words chamai (on the ground, on the earth) and leon (lion).

This is a rather old lizard family since fossil records are known from as early as the early Tertiary.

Distribution and habitat

The main distribution of Chameleons is Africa and Sri Lanka, India and Asia Minor. Different members of this family inhabit all kinds of biotopes like tropical and montane rain forests, savannahs and sometimes semideserts and steppes. Chameleons are mostly arboreal and are often found on smaller bushes and shrubs rather than on taller trees. Some species, however, live on the ground under foliage.

Behaviour

All Chameleon species are diurnal. Their main activity is in the morning and in the evening. Chameleons are not active hunters but rather sit motionless for hours and wait for a prey to pass by. They mainly feed on different arthropods and small vertebrates. Chameleons live mostly solitary and are quite aggressive toward other members of the same species.

Change of colour

Some Chameleon species are able to change their body colour, which made them one of the most famous lizard families. Contrary to popular belief, this change of colour is not an adaptation to the surroundings but rather an expression of the physical and physiological condition of the lizard. The skin colour is changed under influence of mood, light and temperature. The skin colour also plays an important part in communication and rivalry fights.

Chameleons have specialized cells that lie in two layers under the chameleon's transparent outer skin. The cells in the upper layer, which are called chromatophores, contain yellow and red pigments. Below these chromatophores is a another cell layer. Cells of this layer are called guanophores and they contain the colourless crystaline substance guanin. These guanophores reflect amongst others the blue part of incident light. If the upper layer of chromatophores is yellow, the reflected light becomes green (blue plus yellow). A layer of dark melanin containing melanophores is situated even deeper under these blue and white light reflecting guanophores.These melanophores influence the lightness of the reflected light. All these different pigment cells can relocate their pigments, thereby influencing the colour of light which is reflected.

Classification of Chamaeleonidae

Family Chamaeleonidae

• Subfamily Chamaeleoninae (typical chameleons)
  • Genus Bradypodion
  • Genus Calumma
  • Genus Chamaeleo
  • Genus Furcifer
• Subfamily Brookesiinae (dwarf chameleons)
  • Genus Brookesia
  • Genus Rhampholeon

External links:

• http://www.chameleonjournals.com/ This includes a page on the husbandry (care and feeding) of chameleons.
• http://www.afriherp.org