Scorpion

Scorpions are predatory arachnids of the order Scorpiones. They have eight legs[1] and are easily recognized 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 / 0.3 in. (Typhlochactas mitchelli) to 23 cm / 9 in. (Heterometrus swammerdami).[2]

The evolutionary history of scorpions goes back to the Silurian period 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,[3] with 13 extant (living) families recognised to date. The taxonomy has undergone changes and is likely to change further, as genetic studies are bringing forth new information.

All scorpions have a venomous sting, but the vast majority of the species do not represent a serious threat to humans and in most cases healthy adults do not need any medical treatment after being stung.[4] Only about 25 species are known to have venom capable of killing a human.[5]:1 In some parts of the world with highly venomous species human fatalities regularly occur, primarily in areas with limited access to medical treatment.[4]