Meet the (terrifying) neighbours

Charles Boyle

As winter comes and you’re out collecting firewood in the Gondwanan forests of the northern rivers you may meet the Northern Rivers Funnel Web (Hadronyche formidablis) aka the Northern Tree Funnel Web.

Formidablis means ‘terrifying/ferocious’, and for good reason – with a total length of up to 125mm (as big as your hand), this is by far the biggest of all Funnel Web spiders and is easily the world’s biggest deadly spider.

The Sydney and Tree Funnel Webs are well known for their venom, but in all there are thirty-five species of Funnel Web found in eastern Australia, all the way from Tasmania to Cape York – and they’re all venomous.

The Northern Rivers Funnel Web is found in wet sclerophyll and rainforests from Noosa to Newcastle. The northern rivers is right at the centre of the spider’s range, and where you’re most likely to meet one.

Not so grounded

Hadronyche formidablis is secretive, nocturnal, and can be found more than thirty metres above the ground so they are poorly understood.

They make their burrows in rotting logs and crevices, borer holes and natural cavities in trees, preferring strangler figs and the deeply fissured bark of the Mountain Casuarina (Casuarina cunninghamiana), avoiding bark-shedding trees. Silken trip-lines radiating from the tunnel entrance alert the spider to approaching prey – insects, lizards, frogs – anything small enough to be ambushed.

The female never leaves her burrow and continues to grow throughout her life – up to at least thirty years – and is most often found in fallen trees (ie firewood). Unlike the smaller, far more venomous males that are commonly encountered on warm wet summer nights searching for a mate, or hiding in shoes and clothing during the day.

Who’s immune?

Funnel Web venom is surprisingly harmless to all mammals – except primates. A dog will show no signs of poisoning from the same dose of venom that can kill a child in just fifteen minutes.

Fortunately, in our forests these spiders are under constant threat of predation by antechinus, bats, quolls, scrub turkeys, lyrebirds and even cane toads. The lack of native predators in Sydney allows Sydney Funnel Web spiders to display aggressive behaviour that would quickly make them dinner in the northern rivers.

Was I bitten?

H. formidablis is cousin to the deadly Sydney Funnel Web and it has a similar neurotoxic venom. The spiders don’t always inject poison when they bite. Sydney Funnel Webs envenomate in 17 per cent of bites but H. formidablis delivers venom in more than 75 per cent of bites.

There is no ambiguity – you know if you’ve been bitten by a Funnel Web spider. The powerful black fangs can puncture shoe leather and they inflict an extremely painful bite with bleeding puncture wounds, and the spiders often strike repeatedly.

Typically after about thirty minutes early signs of envenomation begin: sweating, goose-bumps, tingling mouth and facial twitches. This is followed by increased pulse and blood pressure. Left untreated, the symptoms become more acute – vomiting, confusion, shortness of breath, muscle spasms and fluid in the lungs. Then comes pupil dilation and unconsciousness. Death follows, caused by fluid on the brain (cerebral oedema).

Anti-venom

There have been thirteen documented deaths from Funnel Web spider bite since the colonisation of Australia. No doubt there have been many unrecorded deaths as the species was not formally named until 1877.

In Sydney in 1979 Christine Sturges, 32, was bitten by a Funnel Web spider while making a bed and subsequently died. Her widely publicised death inspired Dr Struan Sutherland, head of Immunology at the Australian Commonwealth Serum Laboratories, to develop a vaccine.

The very next year, in 1980, James Cully, aged two, also died from a Funnel Web bite, becoming the spider’s thirteenth and last victim. Just months later, Dr Sutherland’s antivenom was released and there hasn’t been a single death since.

Dr Sutherland also pioneered the concept of using pressure bandages in place of tourniquets in snakebite and spider bite.

Treating bites

If you are bitten by a Funnel Web (or any big black spider), as with a snake bite, immediately apply a pressure bandage and splint to the affected limb and treat the bite as a medical emergency. All local hospitals have stores of antivenom. Patients are typically discharged in 1–3 days and usually make a full recovery.

Statistically, you are thousands of times more likely to be assaulted by a human than bitten by a Funnel Web spider. They are slow, they can’t jump and they don’t want to fight. It is the last resort in self-defence for a creature that can be easily crunched under a boot.

If you are fortunate enough to see one, don’t panic. Take the opportunity to experience an awe-inspiring ancient veteran of Gondwana, perfectly adapted to the forests of the northern rivers. Then run like hell.

Catch and deliver

The Australian Reptile Park milks the Funnel Web spider for its venom to make the anitvenom and they rely on people catching and delivering the spiders to them.

‘Our milking team completed 3,500 milkings in the last year, but the aim is to complete 5,000 milkings to build up venom supplies,’ said Liz Gabriel, head curator at the Australian Reptile Park.

In 2017 a ten-year-old needed 12 ampoules of Funnel Web antivenom – the highest amount of antivenom given to anyone on record. It takes 100–150 milkings to make one ampoule of anti-venom.

The Australian Reptile Park is always accepting Funnel Web spider drop-offs but only the male spider can be milked.