The Tiger Snake (Notechis scutatus) is a highly venomous reptile endemic to Australia, belonging to the elapid family distinguished by fixed front fangs. Its venom ranks among the most potent of any land snake in the world. Found predominantly in the southern regions of the continent, the Tiger Snake is a significant species, responsible for a considerable number of snakebite incidents each year.
Identifying Features and Behavior
Tiger snakes possess a robust, muscular body, typically reaching about 1.2 meters in length, though some regional populations grow up to 2 meters. The head is broad and blunt, often appearing only slightly distinct from the neck.
Identification is challenging due to the snake’s highly variable coloration, known as polymorphism. While the common name suggests distinct cross-bands, many individuals are unbanded or uniformly colored. Colors range from pale yellow and olive to dark brown or jet-black, depending on the snake’s location and subspecies.
The snake is generally shy, preferring to retreat from human encounters. When cornered or threatened, however, the Tiger Snake adopts an unmistakable defensive display. It flattens its head and neck, sometimes raising its forebody off the ground in a posture similar to a cobra, while hissing loudly as a warning.
This defense mechanism signals that the snake is prepared to strike if the threat persists. As a carnivore, its diet primarily consists of frogs, but it also consumes small mammals, birds, and fish. It is active during the day, but may shift to nocturnal activity during warm weather to avoid high temperatures.
Geographic Range and Preferred Environments
The Tiger Snake is distributed across the southern regions of Australia, including Tasmania and various offshore islands. Its range covers the coastal areas of New South Wales, Victoria, South Australia, and parts of Western Australia. This broad distribution results in regional variations in size, color, and venom composition.
The species strongly prefers habitats near water, reflecting its reliance on amphibians for food. Common environments include wetlands, swamps, marshes, creeks, and river floodplains. The snakes are excellent swimmers and utilize dense vegetation for hunting and shelter.
Their adaptability allows them to inhabit dry, rocky areas and suburban fringes, particularly where human development meets natural waterways. Permanent water sources are a consistent factor across their varied habitats, supporting necessary prey density. They seek shelter in hollow logs, under rocks, or in abandoned burrows, becoming inactive during winter months.
The Potency of Tiger Snake Venom
Tiger Snake venom is a complex and potent cocktail of toxins, ranking as one of the most dangerous in the world. The average venom yield is substantial, typically ranging from 35 to 65 milligrams, with a lethal dose for humans estimated to be as low as three milligrams. This high toxicity contributes to the species being a significant cause of serious envenomation in Australia.
The venom targets multiple systems within the body. Highly neurotoxic components, including pre-synaptic and post-synaptic neurotoxins, cause paralysis by disrupting nerve-muscle communication. Additionally, procoagulants target the blood clotting cascade, leading to rapid consumption of clotting factors and systemic coagulopathy.
Symptoms can progress rapidly, sometimes appearing within 15 minutes, depending on the amount of venom injected. Initial signs include localized pain, tingling, and numbness at the bite site, followed by sweating, nausea, and headache. As neurotoxins take effect, the victim may experience ptosis (drooping eyelids) and muscle weakness, progressing to respiratory paralysis.
Myotoxic elements cause muscle damage that can lead to rhabdomyolysis and, in severe cases, acute renal failure. Untreated bites carry a high mortality rate, historically estimated between 40 and 60 percent.
Immediate action following a suspected bite is to apply the Pressure Immobilization Technique (PIT). This involves wrapping a firm pressure bandage over the entire length of the bitten limb and immobilizing it with a splint. The purpose of PIT is to slow the lymphatic spread of venom into the bloodstream, buying time for medical help.
The wound should never be washed, cut, or have suction applied, as these actions accelerate venom absorption. Treatment requires prompt medical intervention using Tiger Snake Antivenom, which is derived from the plasma of immunized horses. The availability of antivenom has significantly reduced the fatality rate associated with envenomation.