Interesting to know:
Scorpions belong to a fairly small order Scorpiones within the class Arachnida. In total there are only some 1,500 species which have been recorded although doubtless others await discovery. All scorpions are nocturnal and the majority come from tropical areas. Throughout the day most species remain underground in self dug burrows although some species (mainly Bark Scorpions of the Genus Centruroides) rest above ground, hanging from rocks and branches or under loose bark. As far as invertebrates go scorpions are relatively long lived with some species reaching 6-7 years.
Most species of scorpion can be kept in small groups and require relatively little in the way of specialized housing. The main requirements (as they are for most invertebrate pets) are that the enclosure is secure and can be maintained at an appropriate temperature and humidity. Scorpions are best kept in a glass aquarium with a good escape proof preferably lockable lid. Many scorpions are good climbers.
The type of substrate used in your terrarium depends on the particular species of scorpion you own, these fall in to two very basic types: Forest species and Desert Species.
Forest species for example - those belonging to the genera Pandinus and Heterometrus - come from Africa and Asia and require warm, humid conditions. A deep layer of peat-free compost (6-7cm) should be placed in the terrarium, this can be covered with orchid bark chippings. The top of the substrate should be sprayed with water every day or so but never to a degree that it becomes very wet. Care should be taken that the substrate does not become moldy or covered in fungus.
Desert species for example those from the genera Centruroides, Buthus and Androctonus (plus many others) require considerably drier conditions. The terrarium should be filled with approximately 10cm of coarse sand, desert scorpions require little moisture and rarely need to be misted.
You can decorate the terrarium with some flat pieces of wood, cork bark or pieces of ceramic plant pot which not only make the enclosure look more attractive but give your scorpions something to burrow under.
Scorpions are nocturnal and as such have no positive requirement for light. The best method for heating the tank is to use a heatmat. A suitably sized heatmat can be bought from you local pet shop (normally those selling lizards and other reptiles have a good range). A good heatmat should maintain the terrarium temperature at 77 degrees Fahrenheit (25°C). You should position the heatmat so that it covers approximately one third of the base of the terrarium. This produces a temperature gradient and the scorpions can move between warm and cooler areas to regulate their body temperature.
It is important to note that if the temperature is too great the scorpions will burrow into the substrate to avoid the heat, unfortunately this brings them closer to the heatmat and there is a danger they will over heat and die. It is for this reason that the heatmat should not cover the entire base of the terrarium and it may be worth turning off the mat during particularly warm summer spells (this obviously depends on where you live).
All scorpions are carnivores eating insects, spiders and even small lizards and snakes. The amount of food required by your scorpion will depend on the species and size. A large scorpion (eg Pandinus imperator) will often eat two or three adult crickets a week. It is best to feed your scorpions at night so that their behavior pattern will more closely resemble that of wild scorpions. The scorpions will not feed properly if kept in unsuitable conditions so left over food may be an indication that something is not right.
If you keep live food for your scorpion then you should also ensure that the live food is kept in appropriate conditions (adequate space, correct temperature and humidity and access to food and water).
The best rule is to never handle you scorpion. Species belonging to the Genus Pandinus or Heterometrus are generally considered docile and relatively harmless however other species are potentially lethal. If you must handle your scorpions it is best to do so very gently with a long pair of foam tipped forceps.