CausesBy Mayo Clinic staff
Scorpions are arthropods — a relative of insects, spiders and crustaceans — and have changed little in the last 400 million years or so.
The average scorpion is about 3 inches (7.6 centimeters) long, but different species can be much smaller or larger. At 8 inches (20 centimeters), the African scorpion is probably the world's longest. Scorpions have eight legs and a pair of crab-like pinchers, giving them a certain fierce look. The venom is carried in a gland on the back of the tail, and when on the attack, a scorpion can flick its stinger over its head with lightning speed. The venom itself contains a complex mix of toxins that affect the nervous system (neurotoxins).
Many people think of scorpions as dangerous pests, but they play a critical role in the ecosystem, consuming large quantities of other arthropods and even small snakes and mice. They're also shy, nocturnal creatures that resist stinging unless provoked or attacked. They can control the amount of venom they release — depending on how threatened they feel — so some stings may be almost entirely venomless.
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