Australia hosts approximately 140 species of terrestrial snakes, many of which are found nowhere else in the world. The continent is globally significant for its reptile fauna and has a higher ratio of venomous to non-venomous snakes than most other regions, with around 100 species possessing venom. This unique distribution results from the dominance of the Elapid family of venomous snakes in the continent’s evolutionary history.
Terrestrial Venomous Snakes
The vast majority of Australia’s medically significant snakes belong to the Elapid family. These snakes are proteroglyphous, possessing short, fixed, hollow fangs permanently located at the front of the upper jaw. The venom delivered through these fangs is primarily neurotoxic.
The Eastern Brown Snake (Pseudonaja textilis) is one of the most widespread and frequently encountered venomous species across eastern Australia, thriving in grasslands, woodlands, and agricultural areas. Its extremely potent venom contains neurotoxins that cause paralysis and anticoagulants that interfere with blood clotting. The Tiger Snake (Notechis scutatus), found predominantly in the temperate regions of southern Australia, is also highly dangerous.
Tiger Snakes often display banded patterns, and their venom contains powerful neurotoxins and coagulants. The Inland Taipan (Oxyuranus microlepidotus) holds the distinction of having the most potent venom of any land snake globally, though it is reclusive and rarely encountered in its arid central habitat. The Coastal Taipan (Oxyuranus scutellatus) is notable for its high venom yield, sometimes exceeding 120 mg in a single bite.
Pythons and Other Non-Venomous Species
Australian terrestrial snakes lacking potent venom are primarily represented by the Python family, which are non-venomous constrictors. Pythons subdue prey by coiling around them and exerting pressure until the animal suffocates.
The Carpet Python (Morelia spilota) is common and widespread, found in diverse habitats from rainforests to urban areas where it hunts rodents. Pythons exhibit a large size range, from the diminutive Pygmy Python (Antaresia perthensis) to the Scrub Python (Simalia amethistina), which can exceed five meters in length. These snakes are typically nocturnal ambush predators, feeding on mammals, birds, and other reptiles.
Other non-venomous groups include the Blind Snakes (family Typhlopidae), which are small, burrowing, worm-like reptiles. Native Colubrid species, such as the Common Tree Snake (Dendrelaphis punctulatus), are also non-venomous and generally harmless to humans. While larger pythons can inflict a painful bite, they pose no venom threat.
Marine and Semi-Aquatic Snakes
The waters surrounding Australia are inhabited by Sea Snakes (subfamily Hydrophiinae), which are evolutionary descendants of terrestrial Elapids. These snakes are fully adapted to marine life, possessing a paddle-like, laterally compressed tail for swimming. They are found predominantly in warm tropical and subtropical coastal waters, including the Great Barrier Reef.
True sea snakes spend their entire life cycle in the ocean, giving birth to live young in the water. They possess specialized glands to excrete excess salt, an adaptation for surviving in a saline environment. Nearly all sea snakes are venomous, but their fangs are small, and they are generally placid.
A separate, less common group is the semi-aquatic Sea Kraits (genus Laticauda), which must come ashore. Krait species possess large ventral scales necessary for traction and often come onto land to digest prey, drink fresh water, and lay eggs. The Yellow-bellied Sea Snake (Pelamis platurus) is a notable exception, as it is pelagic and often found in the open ocean.
Geographic Distribution Across Biomes
The distribution of snake species across Australia is heavily influenced by the continent’s distinct biomes. The tropical northern regions are hot spots for Python diversity, including the large Scrub Python and the nocturnal Olive Python.
The arid and semi-arid zones that cover much of the interior are home to specialized venomous species, such as the Inland Taipan and the Mulga Snake (Pseudechis australis). These Elapids are well-adapted to the extreme heat and rely on the availability of small mammalian prey found in these dry grasslands and deserts.
In the temperate south-east and south-west, the Tiger Snake is prevalent, often found near water sources like wetlands and rivers. The highly adaptable Eastern Brown Snake has successfully colonized a range of environments from the eastern coast’s temperate zones into the arid interior, exploiting human-modified landscapes like farms and peri-urban areas. This distribution pattern highlights how Australia’s diverse landscape has driven the evolution and localization of its unique snake population.