Reptiles are one of the oldest evolutionary groups of vertebrates. They are descendants of fish and amphibians while the modern birds and mammals derive from the evolutionary branch of reptiles. The name "Reptiles" derives from the Greek word “herpeton” that means “creeping animal” and is due to the creeping movement of the reptiles on the ground. Although most people believe that the reptiles lives on the ground and hide in crevices and under rocks, there are several groups that can be found either on trees or in the sea.

Reptiles are ectothermic animals. This means that they are unable to control/regulate their body temperature through internal metabolic processes. However, they have the ability to regulate their temperature through their behavior, utilizing head from solar radiation and several thermal microenvironments in encountered areas.

The body of reptiles is covered with scales made of a substance called keratin. These scales are dry, soft exteriors of the skin and their primary role is to prevent water loss from the body. The various colorations of the reptiles body are ought to the present of chromatophores cells just beneath scales’ surface. The various color patterns that can be observed in reptiles are a result of adaptation to each species way of life and behavior.

Reptiles are able to discard the outer layer of their skin several times during the active season with a process called “shedding”. This outer layer is being replaced by a new fit layer. In snake this layer is being shed uniform like a shirt while in lizards and turtles, the sheding procedure is taking place segmentaly.

Reptiles breath air using well-formed lungs while their circulatory system constitute from blood vessels (vain and arteries) and a heart with three chambers (two atria and one ventricular).