Home | Arachnids | Spiders | Tarantulas and Other Spiders – Dangerous vs. Beneficial Species – Part 2

Tarantulas and Other Spiders – Dangerous vs. Beneficial Species – Part 2

In Part I of this article, we learned that less than 1% of the world’s 40,000+ spider species are dangerously venomous.  Today I’d like to highlight their valuable role as insect predators and point out a few reasonable precautions that should be taken when keeping spiders in captivity.

Hunting Methods and Diet

Spiders consume animals ranging from mites to birds.   Not all ensnare their prey in webs…some hunt by running (wolf spiders), Misumena vatia with waspswimming (European diving bell spider), spitting silk (spitting spider), hiding in flowers (crab spider), throwing webs (bolas spider), luring fishes while floating (fishing spiders) or rushing from burrows fitted with hinged doors (trap door spider).

However, all spiders consume insects, including agricultural pests and disease-bearing species, to some degree.  Field research has shown that harmful flies comprising over 60% of the diet of certain web-building species.  It is estimated that the weight of the insects consumed yearly by spiders in New Zealand exceeds that of the island’s human population!

Precautions – Bites and Urticating Hairs

The fact that so few spiders are dangerous to people should not be taken as a license to ignore caution when dealing with them. Just as with bees and other venomous animals, allergic persons can be injured or killed by the bites of relatively benign species, and potentially fatal infections can be associated with the bite of any animal.

Also, many tarantulas shed urticating (irritating) 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.

That being said, 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 plastic tongs or by ushering them into a container.

Further Reading

The diving bell spider is certainly one of the world’s most interesting invertebrates – living within a submerged shelter that exchanges oxygen with the surrounding water and swimming after small fishes!  To read more, click here.


Misumena vatia with wasp image referenced from wikipedia and originally posted by Olei.


  1. avatar

    Hey very interesting blog!

About Frank Indiviglio

Read other posts by

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.
Scroll To Top