Funnel web spiders
More than 30 species of the highly dangerous funnel web spider exist throughout Australia. There is known to be at least one species in Papua New Guinea as well. The best known is the Sydney funnel web (Atrax robustus) which is found only within a 160 km radius of Sydney. The male is more dangerous than the female, which is unusual in the spider world. The male Sydney funnel web is also Australia's most dangerous spider, capable of causing death in as little as 15 minutes. However in most cases of bites on humans little venom is injected and no symptoms develop. This is not the case with bites to primates, as they appear to be particularly susceptible to funnel web venom. An antivenom was introduced in 1980 and since then no definite funnel web connected deaths have been recorded. Also, time spent by bite victims in hospital has been greatly reduced. Prior to this, however, 13 known fatalities associated with bites from this spider were recorded.
Sydney funnel web spiders are large, black, aggressive creatures with large downward-pointing powerful fangs. The males live in burrows or rock crevices which they line with silk. They attach external silk trip lines to the burrows to alert them to possible prey or mates. Colonies of more than 100 spiders may be found. The funnel webs also like to live around house foundations. The male spiders in particular often wander into houses in the summer, especially during wet weather.
All funnel web spiders belong to either the genus Atrax or Hadronyche. Spiders of both genera and sexes are highly aggressive and will rear up ready to strike when disturbed. Identification and classification of funnel web spiders can be difficult because some species resemble the less dangerous trapdoor spiders, wolf spiders or black house spiders. All funnel webs have small closely grouped eyes, large downward-pointing fangs, long legs, a large hairy abdomen and a shiny head/thorax. The abdomens are black in males and brown or blue in females. Funnel webs can have a body length of up to 5cm. Females have shorter legs and a bigger abdomen than males and may live for up to 20 years. Males on the other hand live for only three to five years. Female funnel webs spend most of their time in their burrows where they raise their young. They can lay over 100 eggs at a time. The spiderlings hatch after three weeks and stay with their mother for the first few months. They then move out and make their own burrows. Males leave these burrows once they reach maturity and spend most of their time wandering in search of mates and food.
Numerous funnel web spider species are found throughout Australia. These include the northern or tree-dwelling funnel web (Hadronyche formidabilis) found in northern New South Wales and southern Queensland, as well as species found in Victoria, South Australia and Tasmania. There is little information on the relative venom toxicity of most of these spiders and the danger they may pose to man. All funnel web spiders should be regarded as potentially dangerous to humans. On the other hand, funnel web spider antivenom has only been required for bites in southern Queensland, New South Wales and the Australian Capital Territory.