Australian Redback Spider, Red-backed Spider
Latrodectus hasselti
Theridiidae (Cobweb Spiders), Order Araneae
Physical Description
The spider has a globular, bulbous abdomen characteristic of cobweb spiders, contrasted with a much smaller, slender cephalothorax and relatively long, thin legs. Females are significantly larger than males, displaying a stark dimorphism.
Size Estimate
Adult females typically have a body length of about 10 millimeters, with a leg span reaching up to 3 to 4 centimeters. Males are much smaller, around 3 to 4 millimeters.
Coloration & Markings
The adult female is intensely black with a prominent, unmistakable bright red or orange longitudinal stripe or hourglass-shaped marking on the dorsal surface of the abdomen.
Web Type
Constructs an irregular, three-dimensional tangle web or cobweb, typically built in sheltered, dark locations near the ground, featuring sticky vertical catching threads.
Eye Arrangement
Eight small eyes arranged in two transverse rows of four, typical of the Theridiidae family.
Leg Characteristics
Legs are long, thin, darkly colored, and relatively smooth, though they may have subtle spines. When resting in the web, the legs are drawn in closely to the body.
Venom & Safety Information
Venom Information
Contains a potent neurotoxin called alpha-latrotoxin, which affects the nervous system, causing severe pain and systemic symptoms in humans.
Medical Significance
Medically significant. A bite causes intense localized pain that radiates outward, sweating, nausea, and muscle cramps. Antivenom is available and highly effective for severe systemic envenomations.
Safety Recommendations
Wear gloves when gardening or reaching into dark, undisturbed spaces. If a redback is found indoors, relocate it safely using a jar and stiff paper, or leave it alone if outdoors.
Habitat & Behavior
Habitat & Range
Native to Australia and widely distributed throughout urban, rural, and natural environments, often found in dry, sheltered microhabitats such as under logs, rocks, garden sheds, outdoor furniture, and mailboxes.
Behavior & Temperament
Timid and non-aggressive, relying on retreat or playing dead when disturbed. Bites typically occur only when the spider is accidentally pressed against human skin.
Diet & Prey
Feeds primarily on insects, including beetles, flies, and ants, and occasionally captures larger prey such as slaters, small lizards, or other spiders trapped in its sticky web.
Seasonal Activity
Active year-round in warmer climates, with peak activity and mating occurring during the warmer summer months.
Description
The Australian Redback Spider is one of the world's most recognizable and infamous arachnids. Easily identified by the striking red stripe on its glossy black, spherical abdomen, this cobweb weaver makes its home in sheltered nooks across Australia. Though possessing a potent neurotoxin, it is shy and rarely bites unless inadvertently trapped against clothing or skin.
Key Features
Glossy black body combined with a vibrant red or orange longitudinal stripe or hourglass mark on the dorsal side of the rounded abdomen.
Similar Species
Steatoda species (False Widow Spiders), which lack the bright red stripe and have a broader, less globular abdomen.
Life Cycle
Females produce multiple pear-shaped white or cream-colored silk egg sacs containing hundreds of eggs. Spiderlings disperse via ballooning shortly after hatching, maturing over several months.
Ecological Importance
Acts as an effective natural predator of common household and garden insect pests, helping to regulate local insect populations.
Conservation Status
Not threatened; highly adaptable and thrives in close proximity to human habitations.
Interesting Facts
Male redbacks engage in a dramatic suicidal courtship ritual, actively flipping their abdomens toward the female's mouthparts to increase paternity success.
Photography Tips
Photograph from a safe distance using a macro lens, focusing on the distinct red markings against the glossy black background. Natural indirect lighting avoids harsh reflections on the container.
Identified: 2026-09-12T14:02:28.008388