Tarantula spiders are divided into two categories: old world tarantulas and new world tarantulas. Old world tarantulas include the tarantulas that lack urticating hairs, and instead rely on nothing more than their venomous bites for defense. Old world tarantulas get their name from being more common in Asia and Africa. New world spiders are largely limited to the Americas and they comprise spiders that possess urticating hairs in addition to fangs that deliver venom. New world tarantulas are able to fling their abdominal hairs into their enemies faces, which causes severe irritation in humans. These defensive hairs are known as urticating hairs, and many tarantula owners must exercise caution in order to avoid them. Old world tarantula venom is typically more potent than new world tarantula venom, as old world tarantulas have no other method of defense available to them when faced with enemies. This makes old world tarantula bites relatively dangerous to humans. In fact, sustaining a bite from an old world tarantula can cause muscle spasms, cramps and eventual death unless an antivenom is administered to a human victim in time.
People all over the world keep and breed tarantulas as pets, and the creatures are typically dismissed by experts as being harmless. Most pet tarantulas are new world specimens and while their urticating hairs can cause allergic reactions in humans, medical literature describes the consequences of their bite in humans as being trivial. However, this is not the case with old world tarantulas, as one study described two old world tarantula owners who suffered severe medical problems following a bite from the Lampropelma nigerrimum and Pterinochilus murinus species. The two men experienced identical symptoms, which included severe localized swelling and persistent and agonizingly painful muscle cramps that lasted more than a week. A third man who sustained a bite from the old world Poecilotheria regalis species developed muscle spasms in addition to the symptoms experienced by the other two men. According to researchers, the toxic effects of old world tarantula venom has been documented but largely ignored in medical literature. Although antivenom for old world tarantula bites do exist, researchers have yet to uncover the particular toxins responsible for the serious medical symptoms that result from their bites. Discovering these toxins would be of great scientific and therapeutic benefit.
Have you ever sustained a bite from a pet tarantula?