Australia is known for its diverse wildlife, including spiders. While spiders are common across the continent, the reality for most residents and visitors is not one of constant threat. Over 2,900 species have been identified, with an estimated total of up to 10,000. Many of these are harmless to humans, and serious bites are rare.
Australia’s Spider Abundance
The continent features a wide range of habitats, from arid deserts to lush rainforests, and from coastal areas to dense bushlands. This ecological diversity supports numerous spider species, each adapted to its specific niche.
The warm climate across much of Australia allows spiders to remain active year-round, contributing to larger populations and longer growth periods. An abundant supply of insect prey provides a consistent food source. Australia’s long geological isolation has also resulted in a unique evolutionary history, leading to high biodiversity among its arachnids. This combination of diverse habitats, a favorable climate, plentiful food, and evolutionary factors explains why spiders are so prevalent across the Australian landscape.
Commonly Encountered Species
Many spiders are frequently encountered in Australia, both indoors and outdoors, and most are not considered dangerous to humans. Huntsman spiders, known for their large size and speed, are often found in homes, gardens, and under tree bark. They are typically brown or grey, with a flattened body shape and leg spans that can exceed 13 centimeters. Despite their intimidating appearance, Huntsman spiders are generally not aggressive and their venom is not considered harmful, usually causing only mild pain and swelling if a bite occurs.
Garden Orb-weavers are another common sight, particularly in gardens where they construct large, circular webs at night to catch flying insects. These spiders are stout, typically reddish-brown or grey, and have a leaf-shaped pattern on their abdomen. They rebuild their webs daily and are reluctant to bite, with bites usually resulting in only mild local pain and swelling.
While most Australian spiders are not medically significant, the Redback spider and Sydney funnel-web spider are notable for their venom. Redback spiders are found across Australia and are identifiable by the female’s black body with a distinct red stripe on the upper abdomen. They prefer dry, sheltered areas, often found in sheds, under outdoor furniture, or in other urban environments. Bites can cause intense pain, sweating, and nausea, but antivenom is available, and fatalities are rare.
The Sydney funnel-web spider, a robust, shiny black or dark brown spider, is primarily found within a 160-kilometer radius of Sydney. These spiders prefer cool, damp environments like logs and rocks, and males may wander into suburban areas during warmer, humid months. Their bites are considered a medical emergency, but effective antivenom has been available since 1981, making fatalities extremely rare.
Navigating Spider Encounters
Coexisting with spiders in Australia involves adopting simple safety habits. Most spiders are not aggressive and will only bite if they feel threatened or are accidentally pressed against skin. Always check shoes, clothing, and towels left outdoors before use, shaking them to dislodge any hidden spiders.
To deter spiders from entering homes, reduce entry points by repairing cracks and gaps in walls, ensuring flyscreens are fitted, and using door seals. Keeping outdoor areas tidy, such as decluttering backyards and sheds, and moving woodpiles away from the house, can also reduce potential spider habitats near living spaces. If a harmless spider is found indoors, it can often be safely relocated by covering it with a container, sliding a piece of paper underneath, and releasing it outside.
In the rare event of a suspected bite from a medically significant species like a funnel-web or redback spider, seek urgent medical attention. For funnel-web bites, a pressure immobilization bandage should be applied and emergency services contacted immediately. For other bites, cleaning the area with soap and water and applying a cold compress can help.