Spiders are a normal part of life almost everywhere in Australia, in bushland, backyards and inside homes. Being common is a different thing from being dangerous, though, and the country’s deadly reputation is far bigger than the real risk.1The Conversation. Spider home invasion season: why the media may be to blame for your arachnophobia Much of Australia’s spider life is also found nowhere else on Earth, so the numbers reflect a rich native fauna rather than an infestation.
How Many Kinds of Spiders Live in Australia
A thorough survey of the jarrah forest in south-west Western Australia found 287 spider species from 46 families.2Pacific Conservation Biology. Exhaustive sampling in a Southern Hemisphere global biodiversity hotspot: inventorying species richness and assessing endemicity of the little known jarrah forest spiders The survey was judged about 93 to 95% complete, which means even careful counts leave a few species unfound.3Pacific Conservation Biology. Exhaustive sampling in a Southern Hemisphere global biodiversity hotspot: inventorying species richness and assessing endemicity of the little known jarrah forest spiders About 77% of the described species were known only from Australia, and more than a third of those had only ever been found in Western Australia, mostly in the south-west.4Pacific Conservation Biology. Exhaustive sampling in a Southern Hemisphere global biodiversity hotspot: inventorying species richness and assessing endemicity of the little known jarrah forest spiders
“Described” means a species has been formally named and written up by scientists, and many Australian spiders are still waiting for that step. That is why even a survey judged nearly complete can turn up a new kind, and why no one can give an exact national total.
So many species exist nowhere else because Australia has been an island continent, isolated for millions of years. Many spider families trace back to an ancient southern supercontinent, and isolation let local species evolve without ever spreading overseas. Visitors often notice unfamiliar spiders for this reason, even if they know the spiders at home well.
The great majority of kinds are small and spend their lives in leaf litter, bark and soil, so most are rarely noticed. Seeing several webs on a bush walk is normal, not a sign of danger.
Spiders are also a steady part of the ground life. In jarrah forest soil and leaf litter, they were one of the regular groups alongside earthworms, ants, beetles and termites.5Australian Journal of Soil Research. Changes in the abundance and activity of certain soil and litter fauna in the jarrah forest of Western Australia after a moderate intensity fire Their numbers in that soil held steady through nearly three years after a moderate fire.6Australian Journal of Soil Research. Changes in the abundance and activity of certain soil and litter fauna in the jarrah forest of Western Australia after a moderate intensity fire
Different regions have their own spiders. Some groups, such as the ground-dwelling Aname spiders, have spread across the whole continent and adapted to deserts, tropics and temperate zones.7PubMed. Diversification of the mygalomorph spider genus Aname (Araneae: Anamidae) across the Australian arid zone: Tracing the evolution and biogeography of a continent-wide radiation In the relatives of the widespread spider Tetrarchia, studied across the country, darker individuals are more common where it rains more and orange ones where it is drier.8Functional Ecology. Precipitation shapes colour polymorphism in a widespread spider
Spiders You Are Likely to Find at Home
Many spiders have adapted to live alongside people in houses, sheds and gardens.9Department of Health, Victoria. Spiders – pest control Other spider populations are shrinking as their natural habitat is destroyed.10Department of Health, Victoria. Spiders – pest control
Huntsman spiders, the large flat spiders often seen on walls and in cars, are harmless to people.11Backyard Buddies. Huntsman Spiders – Backyard Buddies They eat mosquitoes and cockroaches, and cockroaches are a favourite.12Backyard Buddies. Huntsman Spiders – Backyard Buddies They are also food for birds, reptiles, mammals, larger spiders and spider wasps.13Field of Mars Environmental Education Centre. Huntsman spider fact sheet
Huntsmen are big, flat and long-legged, with legs held out sideways. They are fast and can dart across a wall or down a car visor, which startles people, but they aren’t aggressive and prefer to flee. If one is indoors, a cup and a piece of card is enough to carry it outside.
The redback, a widow spider, thrives in human-disturbed environments.14PubMed Central. Realized niche shift of an invasive widow spider: drivers and impacts of human activities Human impact was the strongest predictor of where redbacks live, ahead of climate.15PubMed Central. Realized niche shift of an invasive widow spider: drivers and impacts of human activities Sheds, outdoor toilets, garden furniture, pot plants and spots under ledges are typical hiding places. Whether redbacks establish in a new area still depends heavily on local warmth and humidity.16PubMed Central. Realized niche shift of an invasive widow spider: drivers and impacts of human activities Females are black with a red or orange stripe on the back.
Other regulars are easy to learn. Daddy long-legs spiders hang in tangled webs in ceiling corners and are harmless. Black house spiders build lacy funnel webs around window frames. White-tailed spiders are slim and dark, with a pale tip on the abdomen.
Seal gaps around doors and windows, fit screens, and clear clutter from garages and sheds. Wear gloves when gardening or reaching into dark spaces.
How Often Spiders Actually Hurt People
Spiders were the most common cause of hospital stays for bites and stings in Australia in 2002 to 2005, with 3,887 cases over those years.17Australian Institute of Health and Welfare. Venomous bites and stings in Australia to 2005 That works out to about 6.5 hospital stays per 100,000 people, a small risk for any one person.18Australian Institute of Health and Welfare. Venomous bites and stings in Australia to 2005 Over 2000 to 2013, spiders caused about 30% of venom-related hospital admissions, close behind bees and wasps at 31% and well ahead of snakes at 15%.19PubMed. Injury trends from envenoming in Australia, 2000-2013 Most people admitted for venom injuries were aged 30 to 44.20PubMed. Injury trends from envenoming in Australia, 2000-2013
A hospital stay means someone was ill enough to be admitted, so these counts leave out the many bites that cause only mild pain or redness and are never recorded. Spiders topping the list reflects how often people meet them, not how dangerous the average spider is.
Only a very small share of spider species can give people a bad bite, and no deaths are known in recent decades.21The Conversation. Spider home invasion season: why the media may be to blame for your arachnophobia The Sydney funnel-web causes about 30 to 40 bites a year.22Burke Museum. Myth: Deadly Australian/Brazilian spiders No one has died from a funnel-web bite since antivenom, a treatment made to neutralise the venom, was introduced in 1980.23Burke Museum. Myth: Deadly Australian/Brazilian spiders From 1927 to 1979 there were 13 or 14 known deaths, under 1% of bites.24Burke Museum. Myth: Deadly Australian/Brazilian spiders
That drop is linked to the treatment, not to funnel-webs becoming less venomous. A funnel-web bite is a genuine emergency, but a treatable one.
If you suspect a funnel-web bite, apply a firm pressure bandage, keep still and call 000. For a redback bite, use a cold pack rather than a pressure bandage, and seek help if the pain spreads or persists. Most other bites need only washing and a cold compress. Ambulance and hospital teams carry or can reach antivenom.
Some feared spiders are not as bad as their reputation. White-tailed spiders have been blamed for flesh-damaging wounds, but the evidence for that link is weak.25Burke Museum. Myth: Deadly Australian/Brazilian spiders
Where Funnel-Webs Live
The Sydney funnel-web is now known to be three related species.26PubMed Central. The world’s most venomous spider is a species complex: systematics of the Sydney funnel-web spider (Atracidae: Atrax robustus) One lives north and south of Sydney Harbour across the Sydney Basin.27PubMed Central. The world’s most venomous spider is a species complex: systematics of the Sydney funnel-web spider (Atracidae: Atrax robustus) A second ranges west into the Blue Mountains and south to about Stanwell Tops.28PubMed Central. The world’s most venomous spider is a species complex: systematics of the Sydney funnel-web spider (Atracidae: Atrax robustus) A third is found within about 25 km of Newcastle.29PubMed Central. The world’s most venomous spider is a species complex: systematics of the Sydney funnel-web spider (Atracidae: Atrax robustus)
Someone in Newcastle, the Blue Mountains or Sydney itself may be in Sydney funnel-web country, but outside those areas that spider isn’t found, though related funnel-webs live elsewhere in eastern Australia. That limited range is the main reason the most feared spider is far less likely to be met than the national reputation suggests.
Funnel-webs are glossy dark brown to black, with a shiny front body section and no pattern, and they are stocky rather than long-legged. They live in silk-lined burrows in the ground or in crevices, with trailing silk threads at the entrance that signal passing prey. Most are never seen, because they stay in the burrow unless a male goes wandering.
They favour damp spots. Funnel-webs are more common on low, moist ground than on hot, dry hillside.30Bulletin of the British Arachnological Society. Seasonal activity patterns in Sydney funnel-web spiders, Atrax spp. (Araneae: Hexathelidae) Tree-dwelling funnel-web relatives favour wet, rotting logs over dry, hard ones.31Journal of Zoology. Population structure in a saproxylic funnelweb spider (Hexathelidae: Hadronyche) along a forested rainfall gradient In these areas, damp gardens, rockeries, leaf litter and rotting timber are where to take care.
In funnel-web country, shake out shoes and clothes left outside, and wear gloves and shoes when gardening. Check pools in the morning, as funnel-webs can survive hours underwater.
When Spiders Are Most Active
Funnel-webs are rarely seen moving around between May and November, in the cooler months.32Bulletin of the British Arachnological Society. Seasonal activity patterns in Sydney funnel-web spiders, Atrax spp. (Araneae: Hexathelidae) Adult males, the wanderers people most often find, mostly roam in summer and autumn.33Bulletin of the British Arachnological Society. Seasonal activity patterns in Sydney funnel-web spiders, Atrax spp. (Araneae: Hexathelidae) Adult females wander mainly in spring and summer, often after heavy rain.34Bulletin of the British Arachnological Society. Seasonal activity patterns in Sydney funnel-web spiders, Atrax spp. (Araneae: Hexathelidae) Males leave their burrows to look for females, so they are the ones most often found crossing lawns, paths and floors, while females spend most of their time in or near the burrow.
Spiders are generally more active in summer, but risk varies with location, season and conditions.35Assurance First Aid Kits. Spider Season in Australia: When to Be Alert and What to Keep in Your Redbacks and funnel-webs have different seasonal patterns and ranges.36Assurance First Aid Kits. Spider Season in Australia: When to Be Alert and What to Keep in Your Warm weather brings more insects and more spider activity, and males leave burrows or webs to find mates, sometimes wandering indoors.
Heavy rain can soak burrows and ground-level shelters, pushing spiders to drier places, including garages and houses. That is one reason people see spiders after a storm, even though the number living nearby has not changed. Check garden gloves and boots more often in summer, keep doors shut at night in the warm months, and take extra care moving outdoor items after storms.
Spider Rain and Silk-Covered Towns
In ballooning, spiders climb to a high point and release silk threads that lift them on air currents, so they travel wherever the wind takes them.37Animals. Millions of Spiders Coat an Australian Town With Silk A young spider climbs to the tip of a fence post, twig or grass stem and faces into the breeze. It lifts its abdomen and releases silk, and when the threads are long enough the air carries it off. It can’t steer, and many settle only a short distance away.
Ballooning is how many small and young spiders spread to new ground, and it happens quietly all the time. Floods can trigger mass ballooning as spiders escape waterlogged ground, and that makes it visible.38American Entomologist. Who’ll Stomp the Rain? In 2012 around Wagga Wagga, record rain drove spiders and 13,000 people from their homes, and webs blanketed the countryside.39Animals. Millions of Spiders Coat an Australian Town With Silk In 2015 Goulburn saw millions of baby spiders appear to rain from the sky.40American Entomologist. Who’ll Stomp the Rain?
The spiders involved are mostly tiny young ones, escaping danger rather than attacking. The silk and spiders disappear within days or weeks.
The silk sheets can come from failed launches, when strong breezes blow threads back onto trees again and again.41Animals. Millions of Spiders Coat an Australian Town With Silk Fields and trees end up covered in shiny silk, sometimes called angel hair.42American Entomologist. Who’ll Stomp the Rain? The sheets are made of countless fine strands from many spiders, not one huge web built by a single animal.