Entomology
How does the poison in tarantulas and scorpions produced? Is it fatal to humans?
Kevin: Tarantulas and scorpions produce poison in a way very similar to the way we produce spit -- they have specialized glands that create and excrete the chemicals, called poison glands or venom glands. Tarantulas (and other spiders) inject the venom with a bite through their fangs, while scorpions inject their venom using a stinger located at the end of their tail. Tarantula bites are not considered to be "deadly" to humans, and most species sold in pet stores are gentle and unlikely to bite unless severely provoked (as in bonked on the head!). There are, however, a few species that are somewhat more aggressive and have a more dangerous venom. Examples of these are the Asian Ornamental Tarantulas (Poecilotheria spp.) and the African Baboon spiders (Pterinochilus spp.). These can cause swelling, intense pain, cramps, and inflammation around the bite area. The most commonly sold "pet store" species, the Chilean Rose Tarantula, rarely bites, and when it does, it hurts about like stapling your hand -- not a pleasant feeling but it goes away quickly. Most scorpions are also not dangerous to people. There are, however, several species that are considered to be deadly, mostly from Africa and the Middle East. Here in the USA, only the bark scorpion Centruroides exilicauda (= Centruroides sculpturatus in the older papers) that lives in the southwestern states (like Arizona) is deadly to people, and then generally only to the very young or the very old, or to people already ill with another disease. Again, the common "pet store" species, the Emperor Scorpion (Pandinus imperator) is not likely to sting, and even when it does, its venom is not dangerous to humans. I hope this answers your question. If you are planning to keep a tarantula or scorpion as a pet, be sure to read a good book or two on how to care for it. They aren't really the best animals to have as pets -- they don't do any tricks, they don't come when they are called, but then they don't wet on the rug either, so I suppose that is a plus. Dr. Mike