Hexathelidae, funnel web spider

Atrax robustus

Atrax robustus, Sydney funnel web, female

Atrax robustus, commonly known as the Sydney funnel web spider, female above and male below. This spider is possible the deadliest in the world. It is native to the New South Wales forest and urban areas in Australia in a 100 km radius of Sydney. Its body length ranges from 1.5 - 3.5 cm, and it has very large fangs that are strong enough to pierce through a human toenail. Both sexes are shiny and dark coloured ranging from brown to black to blue/black. The spinnerets are usually visible from above.

In its natural habitat it burrows in humid places, preferring moist sand or clay. It constructs a silk-lined burrow with an open, funnel entrance from which radiates trip-lines to detect prey. When prey is detected the spider rushes out and quickly injects venom to subdue the victim. Often the spider will hold on to the prey biting it repeatedly. Normal prey items include beetles, cockroaches, millipedes and frogs, etc. It is very aggressive when threatened rearing up on its hind legs to display the venomous fangs. Females tend to stay in their burrows, but males wander during the warmer months searching for a female to mate. Males take around 4 years to reach sexual maturity and females a little longer. The male locates the female by the pheromones she releases. A female lays between 90 - 120 eggs. They are active mainly at night as the heat and sunlight during the day time would cause them to dehydrate.

Its venom attacks the nervous system and affects the functioning of all the major organs. A bite from a male is 5 times as venomous as a bite from a female, and is capable of killing a human. Antivenom was first made in 1981, and since then there have been no fatalities. One dose of antivenom requires venom milking from around 70 spiders.

Atrax rabustus, Sydney funnel web, male