Funnel Web Spiders are some of the worlds most deadly spiders and are found in coastal and mountain regions of eastern and southern Australia. Funnel Web Spiders are found in two genera of the family ‘Hadronyche’ (which is not associated with any known human fatalities) and Atrax (which is known to have killed 13 people).
Funnel Web Spiders are notorious for the inclusion of the Sydney funnel-web spider (Atrax robustus), native to eastern Australia. There are other genera in family ‘Hexathelidae’, however, these do not have the notorious reputation of the Funnel Web Spiders.
Funnel Web spiders are found in:
- New South Wales
- the Australian Capital Territory
- South Australia
Funnel Web Spider Characteristics
Funnel Web Spiders are medium to large in size, with a body length ranging from 1 centimetres to 5 centimetres (0.4 inches to 2 inches). Funnel Web Spiders are dark in color, ranging from black to brown, with a shiny head and thorax. Some of these spiders greatly resemble tarantulas. Female Funnel Web Spiders are stockier than males, with shorter legs and a larger abdomen, which may be brown or bluish. Funnel Web Spiders eyes are small and closely grouped.
Funnel Web Spiders have fangs which point straight down and do not cross each other. They have ample venom glands that lie entirely within their chelicerae. Their chelicerae and fangs are large and powerful. Although Funnel Web Spiders are rather small compared to the true tarantulas, they should not be handled without taking substantial precautions, because their fangs have been known to penetrate fingernails and soft shoes, resulting in dangerous bites.
Funnel Web Spiders are probably one of the three most dangerous spiders in the world and are regarded by some to be the most dangerous.
Funnel Web Spider Habitat and Spider Webs
Funnel Web Spiders live in burrows in sheltered positions in the ground, or in stumps, tree trunks or ferns above the ground. Their burrows are lined with a sock of opaque white silk and several strong strands of silk radiating from the entrance.
Funnel Web Spider Diet
Female Funnel Web Spiders can live very long lives, possibly up to 20 years. They are rarely seen except during tree felling, excavation or landscaping work.
Female Funnel Web Spiders are sedentary and spend their entire lives inside the burrow, only venturing out momentarily to grab passing prey.
Funnel Web Spider prey consists of insects and small vertebrates such as lizards and frogs.
Funnel Web Spider Reproduction
Young Funnel Web Spiders are raised inside the burrow. After the first couple of molts female Funnel Web Spiders leave the maternal burrow, dispersing on foot to build their own burrow.
Juvenile male spiders remain in the burrow until their final adult molt. Males mature at 2 – 3 years then vacate the burrow in search of a mate.
Funnel Web Spider Venom
While some very venomous spiders may give dry bites, Funnel Web Spiders do so much less frequently. It appears that approximately 10% to 25% of their bites will produce toxicity, however, the likelihood cannot be predicted and all should be treated as potentially life-threatening.
Bites from Funnel Web Spiders have caused 13 deaths (seven in children). In all cases where the gender of the biting spider could be determined, it was found to be the male of the species. Most victims were young, ill or infirm.
There is a large number of different toxins in the venom of Funnel Web Spiders. Collectively, the toxins are given the name atracotoxins (ACTX), as all these spiders belong to the subfamily Atracinae.
Although extremely toxic to primates, the venom appears to be fairly harmless to many other animals, including dogs, cats, horses, rabbits, guinea-pigs, chickens and even cane toads. It has been suggested that these animals may be resistant to the venoms effects.
The females venom was thought to be only about a sixth as potent to humans as that of the male, however, recent research has proven this untrue. The bite of a female or juvenile may be serious, however, considerable variability occurs in venom toxicity between species.
Early symptoms of a Funnel Web spider bite include tingling around the mouth and tongue, facial muscle twitching, nausea, vomiting, profuse sweating, salivation and shortness of breath. Patients may rapidly develop agitation, confusion and coma associated with hypertension, metabolic acidosis, dilation of the pupils, generalised muscle twitching and pulmonary edema. Death results from progressive hypotension or possibly raised intracranial pressure resulting from cerebral edema.
The onset of severe envenoming is rapid. In one prospective study, the median time to onset of envenoming was 28 minutes, with only two cases having onset after 2 hours (both had pressure immobilization bandages applied). Deaths may occur within a period ranging from 15 minutes (this occurred when a small child was bitten) to 3 days.
Funnel web spider venom is highly toxic and all species should be considered potentially dangerous. Males wander at night, especially during or after rain and may enter houses.