Sydney Funnel-Web Spider
Atrax robustus
Hexathelidae (Funnel-Web Spiders), Order Araneae. Key family characteristics include deep and broad carapace, long spinnerets, and orthognathathous chelicerae (fangs pointing straight down).
Physical Description
Robust, heavily built body with a glossy, dark blue-black to brownish carapace and abdomen. The cephalothorax is almost hairless and very shiny. The abdomen is densely covered in fine hairs. Males possess a distinctive spur on the second pair of legs.
Size Estimate
Body length ranges from 1 to 5 cm (0.4 to 2 inches) with a leg span of up to 6 to 7 cm. This specimen appears to be an adult.
Coloration & Markings
Uniformly dark, ranging from dark plum, brownish-black, to glossy jet black. The carapace is heavily chitinized and highly reflective, lacking distinct patterns or markings.
Web Type
Tube or funnel-shaped silk webs built in sheltered, moist locations such as rock crevices, under logs, or beneath house foundations. The web features characteristic irregular trip-lines radiating from the entrance.
Eye Arrangement
Eight small eyes grouped closely together on a small tubercle at the front of the cephalothorax, typical of mygalomorph spiders.
Leg Characteristics
Strong, thick legs with visible spines. The legs are fairly uniform in length compared to true spiders, highly muscular, and adapted for digging and subduing struggling prey.
Venom & Safety Information
Venom Information
Contains robustoxin (atracotoxin), a powerful neurotoxin that specifically targets the human nervous system. It is notoriously dangerous to humans and primates, though harmless to most other mammals.
Medical Significance
Extremely high medical significance; regarded as one of the most dangerous spiders in the world. Envenomation causes severe symptoms including muscle spasms, salivation, sweating, and respiratory distress. Antivenom developed in 1981 has resulted in zero recorded fatalities since.
Safety Recommendations
Wear gloves and sturdy shoes when gardening in endemic areas. Shake out shoes and clothing left outdoors. If bitten, apply pressure immobilization bandage and seek emergency medical attention immediately.
Habitat & Behavior
Habitat & Range
Endemic to eastern Australia, specifically within a 100-mile radius of Sydney, New South Wales. Prefers moist, shaded microhabitats in damp forests and well-watered suburban gardens.
Behavior & Temperament
Aggressive when provoked or cornered. Adopts a distinct defensive threat display by rearing up on its hind legs, exposing its large fangs, and dripping venom from the tips.
Diet & Prey
Primarily preys on large insects, beetles, cockroaches, snails, millipedes, and occasionally small vertebrates like frogs and lizards using ambush tactics from the funnel entrance.
Seasonal Activity
Most active during the warmer, humid summer and autumn months, particularly after heavy rainfall when males roam for females.
Description
The Sydney Funnel-Web Spider is an iconic and formidable arachnid of southeastern Australia. With its glossy black carapace, powerful fangs, and aggressive defensive posture, it commands respect. While its reputation precedes it, the development of an effective antivenom ensures that encounters are safely managed.
Key Features
Glossy black carapace, thick muscular legs, orthognathous fangs pointing downward, long spinnerets, and defensive rearing posture.
Similar Species
Mouse spiders (Missulena spp.), which can look similar but usually have a broader head region and lack the specific venom profile of funnel-webs.
Life Cycle
Females lay eggs in silk egg sacs inside their deep burrows. Spiderlings hatch and disperse after the first molt. Males wander from burrows in search of mates during warmer months. Lifespan can reach several years.
Ecological Importance
Acts as an apex invertebrate predator in its native forest and garden ecosystems, helping to regulate populations of larger ground-dwelling insects.
Conservation Status
Not evaluated on the IUCN Red List, but protected in various regional habitats. Populations are stable.
Interesting Facts
Unlike most spiders, male Sydney funnel-webs are more venomous than females because they wander in search of mates, frequently entering human habitations.
Photography Tips
Photograph from a safe distance using a telephoto or macro lens with a tripod. Avoid provoking the spider to prevent defensive strikes. Capture the dorsal view and eye arrangement clearly.
Identified: 2026-09-11T04:13:29.202351