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. Only about 25 of these species are known to have venom capable of killing a human being.
Scorpion stings are painful, but are usually harmless to humans. For stings from species found in North America, no treatment is normally needed for healthy adults, although medical care should be sought for children and for the elderly. More harmful stings from species found in South America, Africa, and western Asia may require medical attention.
First aid for scorpion stings is generally symptomatic and includes strong analgesia or locally applied treatment such as cold compresses. Hypertensive crises are treated with drugs. Antivenom is the specific treatment combined with supportive measures in patients with cardiovascular toxic effects or neuromuscular involvement. Although rare, severe hypersensitivity reactions including anaphylaxis to scorpion antivenin are possible.
Certain scorpion toxins are potential immunosuppressants for the treatment of autoimmune disorders such as rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis. A chemical found in the venom of the deathstalker scorpion are under investigation for the treatment and diagnosis of several types of cancer. Venom of other types of scorpians is also under investigation for the development of anti-malarial drugs. Scorpions for use in the pharmaceutical industry are collected from the wild in Pakistan. Farmers are paid about $100 for each 40 gram scorpion and 60 gram specimens are reported to fetch at least $50,000. The trade is reported to be illegal but thriving.
Scorpions are found on all major land masses except Antarctica. Scorpions did not occur naturally in Great Britain, Japan, South Korea, New Zealand and some of the islands in Oceania, but now have been accidentally introduced in some of these places by human trade and commerce. The greatest diversity of scorpions in the Northern Hemisphere is to be found in regions between the latitudes 23° N and 38° N. Above these latitudes, the diversity decreases, with the northernmost natural occurrence of scorpions being the northern scorpion found in Medicine Hat, Alberta, Canada. Five colonies of scorpions have established themselves in Sheerness on the Isle of Sheppey in the United Kingdom. This small population has been resident since the 1860s, having probably arrived with imported fruit from Africa. This scorpion species is small and completely harmless to humans. At just over 51° N, this marks the northernmost limit where scorpions live in the wild.
Today, scorpions are found in virtually every habitat, including high-elevation mountains, caves and intertidal zones, with the exceptions such as the tundra, high-altitude taiga, and the permanently snow-clad tops of some mountains. As regards microhabitats, scorpions may be ground-dwelling, tree-living, rock-loving, or sand-loving. Some species are versatile and found in every type of habitat in Baja California, while others occupy specialized niches.
Scorpions are also known to glow a vibrant blue-green when exposed to certain wavelengths of ultraviolet light such as that produced by a black light.
All known scorpion species possess venom and use it primarily to kill or paralyze their prey so that it can be eaten. In general, it is fast-acting, but as a general rule they will kill their prey with brute force if they can, as opposed to using venom. It is also used as a defense against predators. The venom is a mixture of compounds each not only causing a different effect but possibly also targeting a specific animal. Each compound is made and stored in a pair of glandular sacs and is released in a quantity regulated by the scorpion itself. Of the 1,000+ known species of scorpion, only 25 have venom that is deadly to humans.
According to the United States National Institute for Occupational Safety and Health the following steps should be taken to prevent scorpion stings: Wear long sleeves, trousers and leather gloves and shake out clothing and shoes before putting them on. Anyone with a history of severe allergic reactions to insect bites or stings should consider carrying an epinephrine auto injector (EpiPen) and should wear a medical identification bracelet or necklace stating their allergy.