Australia is home to diverse spider species, some reaching considerable sizes. Understanding these creatures can demystify their presence and highlight their role in the ecosystem. This article provides insights into their characteristics, behaviors, and how humans coexist with them.
Australia’s Largest Spiders
Australia’s largest spiders include Australian tarantulas (whistling or bird-eating spiders), various huntsman spiders, and golden orb-weavers. Australian tarantulas, robust spiders from genera like Selenocosmia, have body lengths of 3 to 8 centimeters and leg spans up to 16 centimeters, with some species like the Queensland whistling tarantula reaching 22 centimeters. They are typically dark brown to reddish-brown, sometimes with a silvery sheen, and possess large fangs about 1 centimeter long.
Huntsman spiders (Family Sparassidae) are recognized for their long, flattened legs, enabling them to fit into narrow spaces. Their body lengths are typically 1.6 to 2 centimeters, but their leg span commonly reaches up to 15 centimeters, with some native Australian species like Typostola barbata approaching 20 centimeters. Their coloration usually ranges from grey to brown, sometimes with banded legs.
Golden orb-weavers (Nephila pilipes) contribute to Australia’s large spider reputation, primarily due to the substantial size of their females. Females have a body length of 3 to 5 centimeters, with an overall size up to 20 centimeters, while males are significantly smaller (5 to 7 millimeters). These spiders construct expansive, strong orb webs up to a meter across, characterized by their distinct golden sheen.
Understanding Their Behavior and Risk
The behaviors of large Australian spiders are driven by predatory needs and defense mechanisms, not aggression towards humans. Australian tarantulas are primarily burrowing spiders, residing in silk-lined tunnels underground that can be 40 to 100 centimeters deep, or even up to 2 meters. They are generally non-aggressive, preferring to stay within or near their burrows, emerging to ambush prey. When disturbed, some species produce a hissing or whistling sound as a warning. Bites, while painful due to large fangs, are not considered deadly to humans, though they can cause symptoms like severe pain, nausea, and sweating.
Huntsman spiders are known for their speed and ability to move sideways, often surprising people by scuttling across surfaces. They do not build webs for catching prey but actively hunt insects and other arthropods in various locations, including homes. Their flattened bodies allow them to hide in tight spaces, making them appear suddenly. Huntsman spiders are generally shy and will attempt to flee when approached. Bites are rare, occurring only if the spider feels trapped or provoked; the venom is not highly toxic to humans and is not life-threatening.
Golden orb-weavers construct large webs in open forests, woodlands, and gardens, using sticky, golden silk to capture prey. They typically remain in their webs day and night, waiting for insects to become ensnared. These spiders are not considered aggressive and rarely bite humans. If a bite occurs, it is usually mild, causing minor localized pain and swelling, and is not medically significant.
Living Alongside Big Spiders
Coexisting with large spiders in Australia involves understanding their natural behaviors and appreciating their environmental role. Encounters are common in homes, gardens, and vehicles as they seek shelter or prey. Huntsman spiders, in particular, are frequently found indoors in sheltered spaces like behind curtains or in car dashboards.
When encountering a large spider, observe it from a distance and avoid direct contact. If removal from indoors is necessary, a gentle approach is recommended. Place a container over the spider and slide cardboard underneath to safely capture and relocate it outdoors.
These spiders play an important role in controlling insect populations, acting as natural pest controllers in both natural and urban environments. Their presence often indicates a healthy ecosystem. Dispelling myths and understanding that most large Australian spiders pose minimal risk to humans can help foster a more comfortable coexistence.