Scorpions are becoming increasingly popular as pets, especially emperor scorpions. They are not great for handling, but they are quiet, clean and easy to care for. With a lifespan of 6-8 years they are a fairly long term commitment, and finding a pet sitter might be a bit of a problem.
Emperor scorpions are not particularly dangerous, in contrast to some other species of scorpion. Their sting has been likened to a bee sting in that it is painful, but medical attention is not usually necessary. However, some people may have an anaphylactic reaction to the venom (as some people do with bee stings) so it is wise to not take chances. Some people say that emperor scorpions are more likely to pinch you with their pedipalps, and this can be quite painful too. In any case, handling of pet scorpions isn't recommended, in part because of the risks, but also because scorpions are likely to be stressed if handled. Most people recommend that if handling is necessary (e.g. when cleaning cages) a pair of long handled forceps with foam over the grips be used to pick up the scorpion by the stinging end.
Emperors are large scorpions, at around 6 inches long. They are black (with green or brown hues) and have an impressive set of pedipalps ("claws"). As far as scorpions go, they are quite docile, but as mentioned above handling isn't recommended.
Providing the appropriate environment is the most challenging part of keeping scorpions. The proper heat and humidity is vital in preventing problems. Emperors can be kept alone or in groups. If keeping more than one, a larger tank will be necessary, and a good rule of thumb is to have at least a couple more hiding spots than you have scorpions so they can each have their "space." If there is any sign of aggression between the scorpions, however, I'd recommend separating them.
Emperors are native to Africa and live in humid warm environment, and all scorpions are nocturnal. These factors are taken into account when creating a scorpion habitat.
Glass aquarium tanks are probably the easiest housing to use, and they should have a tight fitting secure lid. A 10 gallon tank is sufficient for one scorpion, but a larger one (20 -30 gallon) will be necessary for groups. However, don't give them too much space since it will be difficult for them to catch their prey in a large tank.
There are multiple opinions on the ideal substrate for emperor scorpions - some use soil, some use peat and others use vermiculite. No matter what you choose, it should be fairly deep (3 - 6 inches) to allow the scorpion(s) to dig burrows. Pieces of bark, flat stones, broken ceramic flower pots or even commercial reptile hides should be provided as hiding spots for the scorpions. Providing pieces of sphagnum moss on top of the substrate will also aid in retaining moisture in the environment. Scorpions will move the cage decorations/furnishings around a bit, and although it may not look neat and tidy, it is best to avoid constantly rearranging the furnishings or else the scorpion(s) will become stressed.
The habitat should be maintained at a high humidity level by regular (daily) misting. The substrate should be kept damp, but not wet. If there is mold on the substrate or condensation on the walls of the tank, the humidity is too high.
A temperature gradient should be provided, from about 70-90 F. Many recommend occasionally allowing temperatures of about 100 F. The temperature gradient is important to allow the scorpions to regulate their body temperature as needed. The easiest way to provide the gradient is by using a heating mat designed for use under reptile tanks. This should be placed under no more than about 1/3 of the tank, so the scorpion can move from warmer to cooler temperatures if desired. Always verify that appropriate temperatures are being provided by using accurate thermometers in a few location within the cage. Being nocturnal, scorpions do not have a requirement for UV lighting, and prefer a light-dark cycle with a slightly longer dark period.
In the wild, scorpions eat a variety of invertebrates (insects, other arthropods) and vertebrates including small lizards. In captivity, they seem to do fine with a diet primarily of crickets, supplemented with other insects such as mealworms and moths. An adult emperor will only need 3 -6 adult crickets per week (feed every other day or so). The crickets should be fed a nutritious diet so that the nutritional value is passed on the the scorpions, and the crickets can be dusted with a quality reptile vitamin/mineral supplement every few feedings. Feed at night to replicate the conditions under which scorpions would naturally feed.
A shallow (shallow enough to prevent drowning) water dish should also be provided.