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Tarantulas and Other Spiders: Dangerous vs. Beneficial Species – Part 1

While most people acknowledge that spiders perform a valuable service by consuming harmful insects, there remains the lingering belief that the vast majorities are dangerously venomous, and do more harm than good. Today I’d like to pass along some facts and figures that you may find interesting.


All spiders produce venom, but in most cases it is only potent enough to overcome the invertebrates upon which they feed. Less than 1% of the world’s 40,000+ spider species are capable of delivering a dangerously venomous bite to humans.

The Real Killers

Dogs, horses, pigs and other domestic animals, although enjoying a far more favorable reputation than spiders, actually kill and maim many more people than do our 8-legged neighbors. In fact, far more people are killed yearly in the USA by falling vending machines (I’m guessing in bars?) than by spiders or snakes!

Potentially Deadly Spiders

The most highly venomous Arachnid, Australia’s funnel-web spider (Atrax robustus), has not caused a fatality since the introduction of antivenin in 1981. In the USA, widows (Latrodectus spp.) and the brown recluse spider (Loxosceles reclusa) are potentially dangerous, but antivenin is available. The bite of the world’s largest spider, South America’s 12-inch goliath bird-eater (Theraphosa blondi), is very painful but otherwise harmless.

Other Spider-Associated Risks

The foregoing should not be taken as a license to ignore caution when dealing with spiders. Just as with bees and other venomous animals, allergic persons can be killed by the bites of relatively benign species, and dangerous infections can be associated with the bite of any animal. Many tarantulas shed urticating hairs when disturbed or even when just moving about. A colleague of mine underwent major surgery to remove such hairs, deposited on his hand by a “tame” red-kneed tarantula, from his eye.

I have kept native and exotic spiders since childhood, and have never been bitten because I do not pick up spiders with my hands. I urge you to handle spiders, if at all, with a plastic tongs or by ushering them into a container.


Further Reading

An excellent resource for those interested in spiders, the American Museum of Natural History’s World Spider Catalog is published at http://research.amnh.org/entomology/spiders/catalog/.

Please see my article Tarantulas in Captivity for information on keeping these fascinating creatures at home.

Funnel Web spider image referenced from Wikipedia and originally posted by Zinnmann

Goliath Bird Eating Spider image referenced from Wikipedia and originally posted by Dcoetzee

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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