REPTILE CHARACTERISTICS

Vertebratic organisms	A good sense of smell
Lungs	A good sense of sight
Internal fertilization	Poikilothermic (cold-blooded)
Membraneous eggs	Overwintering by brumation
Snakes	Lizards
No limbs	Four limbs
No eyelids	Eyelids
No earholes	Earholes
Species: adder or viper, grass snake	Species: viviparous lizard

During the previous chapter, the question of wether amphibians were land- or water-dwelling animals was posed. The conclusion was that amphibians are dependent on aquatic environments for their reproduction, but that otherwise they were quite well adapted to life on land.

What about reptiles? Reptiles have descended from amphibians, but do they have a similar relationship with water? The answer is no: unlike amphibians, reptiles are fully adapted to life on land, and usually require only a little water to survive.

The table above lists some key characteristics of all reptiles. It also introduces the two most important groups of reptiles: snakes and lizards.

Reptiles are poikilothermic, which means that their body temperature changes alongside the temperature of their environment. The lizard in the picture is warming itself up on a rock.