The tiger snake (Notechis scutatus) is a highly venomous elapid species native to the southern regions of Australia and its nearby coastal islands, including Tasmania. Classified within the genus Notechis, it is recognized as a single, wide-ranging species despite significant regional variations. This terrestrial predator has earned a formidable reputation due to its potent venom and its ability to adapt to diverse habitats, often inhabiting areas near human settlements.
Physical Characteristics and Identification
The tiger snake is characterized by a robust, muscular body. Mainland populations typically average about 1.2 meters in length, though some individuals reach up to 2.1 meters. The head is broad and blunt, only slightly distinct from the neck.
The common name refers to the distinctive, contrasting cross-bands of dark and light colors, often creamy yellow over olive, brown, or black. However, color is not a reliable identification method, as many populations are entirely unbanded, appearing uniform olive, grey, or jet-black. When threatened, the snake performs a defensive display by flattening its neck and upper body, similar to a cobra, making it appear much wider. The scales are smooth and semi-glossy, typically arranged in 17 to 19 rows around the mid-body.
Geographic Range and Preferred Habitat
Tiger snakes are distributed across the temperate and subtropical zones of southern Australia, extending from Western Australia, South Australia, Victoria, and New South Wales, including Tasmania. Their range also encompasses numerous offshore islands, where isolated populations have sometimes evolved into distinct forms. These snakes strongly prefer environments near permanent sources of water, such as wetlands, swamps, lagoons, and marshlands.
The abundance of amphibians, their primary food source, is a key factor in their location. They are highly adaptable and can thrive near human development, including disturbed agricultural land and suburban fringes, provided water and prey are available.
Venom and Safety Precautions
Tiger snake venom contains a complex, rapid-acting mix of toxins. It includes powerful neurotoxins, which attack the nervous system leading to paralysis and respiratory failure, and procoagulants, which severely disrupt blood clotting. Envenomation can also cause muscle tissue breakdown and subsequent kidney damage.
Symptoms following a bite include localized pain, headache, nausea, and abdominal pain, followed by neurotoxic effects. Neurological signs, such as drooping eyelids (ptosis) and difficulty swallowing, can progress to descending flaccid paralysis within hours. Untreated envenomation is fatal, making immediate first aid and medical intervention imperative.
The immediate first aid for a suspected bite is the Pressure Immobilization Technique (PIT). This involves firmly bandaging the entire limb and immobilizing it with a splint to slow the spread of venom through the lymphatic system. Treatment requires the administration of specific Tiger Snake Antivenom, which contains antibodies to neutralize the venom.
Behavior, Diet, and Reproduction
Tiger snakes are generally solitary and primarily diurnal, though they shift to nocturnal activity during very warm weather to avoid overheating. They are typically shy and avoid confrontation, but if cornered, they adopt a dramatic defensive posture by flattening the body and raising the head.
Their diet is broad but heavily relies on amphibians, especially frogs, which explains their proximity to water. They also prey on small mammals, lizards, birds, and occasionally fish. Prey is subdued quickly using their powerful venom, sometimes combined with constriction.
Tiger snakes are viviparous, meaning they give birth to live young. Mating occurs in the spring, and females give birth in late summer or early autumn. Litter sizes are substantial, commonly ranging from 10 to 64 live offspring, each born fully independent and venomous.