White Tail Spider - Dangerous or Over Rated?

They do not make a web. Instead, they use an existing web to trap and eat other spiders. By acting as if they are trapped in another's web, they are able to lure an unsuspecting pray.

While white tail spiders prefer to live outdoors under bark and plants, they are often found in houses with a favorite hiding location inside of clothing left on the floor.

Whitetail spiders have very distinctive markings, and a distinctive shape. I can usually spot one on the ceiling by its shape, even without wearing my glasses. The photo to the right is a classic example of the ones we find in our house. Notice:

* long slender dark gray body
* pinkish/orange and black striped legs
* white mark at the end of the abdomen
* pale/white patches, which always look to me like horizontal stripes. (these fade with age)

There are two species of white tails found in New Zealand, both originated in Australia. They look very similar without a microscope. They are not huge, with males growing to 12mm and females to 17mm in length.

As we know first hand (no pun intended here), white tail spiders do bite. Most of the reports I have read agree that the bite is immediately painful, with burning, swelling, redness and itchiness at the bite site.

After this there are differing opinions. Current scientific research indicates that for most people the white tail spider bite will cause little harm, as the venom is not poisonous to humans. Although some bite sites may develop into a small wound, these generally heal inside a week.

A contrasting view reported in both New Zealand and Australia media attributes necrotising arachnidism (destroyed skin) to the white tail spider. However, in most of cases, the offending spider was not found, so there is no evidence that the necrotic ulcers are from a white tail spider bite. Whereas, an Australian study of 130 white tail spider bite patients (who captured the spider) resulted in neither infections nor necrotic ulcers. New Zealand conducted similar research with the same result.

No wonder many New Zealander's fear the white tail spider like those in other countries fear the black widow or brown recluse.

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* Spiders can be found nearly everywhere, although they don't live in Antarctica.

* With a a body size of 10cm and a leg span of 25cm goliath bird-eater (a tarantula) is the largest spider in the world. It lives in the rainforests of Central America.

* New Zealand's largest spider is the cave spider with a body size of only 3cm and a leg span of about 13cm.

* In contrast, the world's smallest spider is less than 1/2 mm long and lives in Samoa.

* All spiders are carnivorous and their most common prey are insects.

* Almost all spiders use venom (injected through the fangs) to paralyze their prey before they start feeding.

* Spiders feed on liquids and cannot take in solid food. They mix digestive fluid with the prey's tissue and suck up the partially digested nutrients.