Reptiles (Reptilia) are members of a class of air-breathing, ectothermic (cold-blooded) vertebrates which are characterized by skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors. Modern reptiles inhabit every continent with the exception of Antarctica. Reptiles originated around 320-310 million years ago during the Carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. Four living orders are typically recognized:
''Bitis arietans'' is a venomous viper species found in savannah and grasslands from Morocco and western Arabia throughout Africa except for the Sahara and rain forest regions. It is responsible for causing the most snakebite fatalities in Africa owing to various factors, such as its wide distribution and frequent occurrence in highly populated regions. Two subspecies are currently recognized, including the nominate subspecies described here.
The species is commonly known as puff adder,.. more