Scorpions are predatory arthropods. They have eight legs, a pair of claws and a long tail (sometimes with a venomous stinger at the end, but just exists 25 species capable to kill a human). Its size goes from 9 mm up to 21 cm, and they can be found in all the continents except in Antarctica. Scorpions's exoskeleton glows in the ultraviolet light because of the fluorescent chemicals on it. They are photophobic (as a defence mechanism against its predators) and nocturne. Scorpions kill its preys both, by crushing them or with venom, and they have a pre-oral cavity to digest food as they can only eat liquids. They also have a low metabolism combined with a good food storage organ and an inactive lifestyle which results in that scorpions are capable of survive up to 1 year without feeding.