Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognised by the pair of grasping pedipalps and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger. Scorpions range in size from 9 mm (Typhlochactas mitchelli) to 20 cm (Hadogenes troglodytes).
The evolutionary history of scorpions goes back to the Silurian era 430 million years ago. They have adapted to a wide range of environmental conditions and can now be found on all continents except Antarctica. Scorpions number about 1750 described species.