Venomous snakes, belonging to the suborder Serpentes, possess the ability to produce venom, which serves multiple purposes such as subduing prey, self-defense, and aiding in the digestion process. Typically, this venom is administered through injection via hollow or grooved fangs, though some venomous snakes may not have well-developed fangs. Among the well-known families of venomous snakes, we find Elapidae, Viperidae, Atractaspididae, and certain members of the Colubridae.

Snake Families and Their Australian Representatives

Family	Description	Australian Species
Atractaspididae (atractaspidids)	Purple-glossed snakes, centipede eaters, burrowing asps, Revoil’s short snake, Chilorhinophis, Hypoptophis, Homoroselaps, Macrelaps, Micrelaps, and more.	No Australian native species
Colubridae (colubrids)	Most are harmless, but some have potent venom, and at least five species, including the boomslang, have caused human fatalities.	Green Tree Snake (Dendrelaphis punctulata), Common Tree Snake (Dendrelaphis punctulata)
Elapidae (elapids)	Sea snakes, taipans, brown snakes, coral snakes, kraits, death adders, tiger snakes, mambas, king cobras, cobras, and more.	Inland Taipan (Oxyuranus microlepidotus), Eastern Brown Snake (Pseudonaja textilis), Coastal Taipan (Oxyuranus scutellatus), Tiger Snake (Notechis scutatus), Red-Bellied Black Snake (Pseudechis porphyriacus)
Viperidae (viperids)	True vipers, including Russell’s viper, saw-scaled vipers, puff adders, and pit vipers like rattlesnakes, lanceheads, copperheads, and cottonmouths.	No Australian native species

The toxicity of snake venom is often measured by the murine LD50 test, but assessing the potential threat to humans involves considering several factors. These include the probability of a snake bite occurring, the volume of venom injected during a bite, the efficiency of the venom delivery system, and the specific location of the bite on the victim’s body. Snake venom can exhibit both neurotoxic and hemotoxic effects.

Globally, there are approximately 600 species of venomous snakes.

Top 5 Venomous Snakes of Australia

Australian venomous snakes have a reputation for delivering lethal bites. These snakes have evolved powerful venoms to subdue their prey and defend themselves from threats. Here are five of the most dangerous and well-known venomous snakes in Australia.

1. Inland Taipan (Oxyuranus microlepidotus) – The Most VeThe Inland Taipan: Australia’s Most Venomous Snakenomous Snake in the World

Known as the fierce snake or small-scaled snake, the inland taipan holds the title of the most venomous snake in the world. Found in the arid deserts of central Australia, particularly in parts of Queensland and South Australia, the inland taipan is rarely encountered by humans due to its remote habitat. Despite its lethal venom, the inland taipan is shy and non-aggressive, preferring to avoid confrontation.

• Venom Potency: A single bite from an inland taipan contains enough venom to kill more than 100 adult humans. Its venom consists of powerful neurotoxins, hemotoxins, and myotoxins, which cause paralysis, blood clotting issues, and muscle breakdown.
• Behaviour: The inland taipan is reclusive and quick to retreat. Bites are extremely rare, as this snake is not found near human settlements.
• Habitat: It lives in clay plains and cracks in the ground, where it hunts small mammals such as native rats.

2. Eastern Brown Snake (Pseudonaja textilis) – Australia’s Deadliest Snake

The eastern brown snake is responsible for more snakebite fatalities in Australia than any other species. Found along the eastern and southern parts of the country, including in suburban and rural areas, this highly venomous snake is fast and can be aggressive when threatened. Despite its danger, it plays a critical role in controlling rodent populations.

• Venom Potency: The eastern brown snake’s venom contains potent neurotoxins and blood coagulants. It can cause rapid paralysis and internal bleeding, leading to death if untreated. They are the only snake species in the world that can kill a person in less than 15 minutes.
• Behaviour: It is highly defensive when cornered but will usually flee if given the chance. It raises its head and forms an S-shape before striking rapidly.
• Habitat: This snake thrives in a variety of habitats, from grasslands to urban areas, and is often encountered near homes and farms.

3. Tiger Snakes (Notechis scutatus)

The tiger snake species is usually identified by the distinctive bands along its body, although these stripes can vary depending on the snake’s age and location. Found in southern Australia, including Tasmania, the tiger snake inhabits wetlands, riversides, and coastal areas. It is highly venomous and responsible for several snakebites each year.

• Venom Potency: The venom of the tiger snake contains neurotoxins, myotoxins, and coagulants. It can cause paralysis, severe muscle damage, and blood clotting disorders.
• Behaviour: While the tiger snake is usually shy, it can become aggressive if threatened. When cornered, it flattens its neck and body, resembling a cobra.
• Habitat: Preferring wet, cool environments, tiger snakes are often found near bodies of water, such as swamps, rivers, and marshes.

---

4. Coastal Taipan (Oxyuranus scutellatus)

The coastal taipan is the largest and most dangerous snake in northern Australia. It is extremely fast, highly venomous, and known for its precision when striking. Coastal taipans are found in the tropical and coastal regions of Queensland, the Northern Territory, and northern New South Wales, where they often inhabit sugarcane fields and forests.

• Venom Potency: The coastal taipan’s venom is a mix of neurotoxins that can cause paralysis, organ failure, and death within hours if left untreated. A single bite can deliver enough venom to kill multiple humans.
• Behaviour: Coastal taipans are generally shy and avoid humans, but when provoked, they strike quickly and repeatedly.
• Habitat: Coastal taipans thrive in tropical rainforests, grasslands, and agricultural areas where they hunt rats and other small mammals.

---

5. Red-Bellied Black Snake (Pseudechis porphyriacus)

The red-bellied black snake is one of Australia’s most recognisable reptiles due to its striking black body and bright red belly. Although highly venomous, bites from this snake are less dangerous than those of the taipans or brown snakes, and fatalities are rare. It is commonly found along the eastern coast of Australia, particularly near water sources such as rivers and swamps.

• Venom Potency: The venom of the red-bellied black snake contains neurotoxins, myotoxins, and anticoagulants. While its venom is not as potent as other species, it can cause severe pain, swelling, and tissue damage.
• Behaviour: Red-bellied black snakes are generally shy and non-aggressive. They prefer to escape rather than confront, but they will bite if threatened.
• Habitat: These snakes are commonly found in wet habitats, including forests, creeks, and swamps. They are also often spotted in suburban gardens close to water.

Importance of Venomous Snakes

Venomous snakes play a vital ecological role in Australia’s ecosystems. As apex predators, they help control populations of small mammals, birds, and other reptiles, preventing overpopulation and maintaining a balanced food web. For example, species like the eastern brown snake are instrumental in controlling the population of rodents, particularly in agricultural areas, reducing the need for chemical pest control methods.

In addition to controlling prey populations, venomous snakes themselves are a source of food for larger predators, such as birds of prey and carnivorous mammals. This complex predator-prey relationship is crucial to the health of Australian ecosystems, helping maintain biodiversity and ecological stability.

Snake venom has become an invaluable resource for medical research. Compounds from venom are being studied and used in treatments for heart attacks, blood clots, and neurological disorders. Highlighting the broader significance of venomous snakes beyond their ecological roles, contributing to advancements in human medicine.

Evolution

The evolution of venomous snakes can be traced as far back as 28 million years ago. Snake venom, essentially altered saliva, is employed for immobilising prey and self-defence. This venom is typically administered through highly specialised teeth—often hollow fangs—directly into the bloodstream or tissue of the intended victim.

Recent evidence supports the Toxicofera hypothesis, suggesting that venom, albeit in minimal amounts, existed in the ancestors of all snakes as well as several lizard families. This “toxic saliva” underwent significant evolutionary changes, particularly in snake families commonly deemed venomous, through a process known as parallel evolution.

Most Venomous Snakes of the World

Snake	Region	Subcutaneous LD50 (mg/kg)	Intravenous LD50 (mg/kg)	LD50 in 0.1% Bovine Serum Albumin (mg/kg)
Inland taipan	Australia	0.01	0.025	N/A
Dubois’ sea snake	Coral Sea, Arafura Sea, Timor Sea, Tar River, and Indian Ocean	N/A	0.044	N/A
Eastern brown snake	Australia, Papua New Guinea, Indonesia	0.041	0.053	0.01
Yellow-bellied sea snake	Tropical oceanic waters	N/A	0.067	N/A
Peron’s sea snake	Gulf of Siam, Taiwan Strait, Coral Sea Islands, and other places	N/A	0.079	N/A
Coastal taipan	Australia	0.064	0.105	0.013
Many-banded krait	Mainland China, Taiwan, Vietnam, Laos, Burma	N/A	0.108	0.061
Black-banded sea krait	Eastern coast of the Malay Peninsula and Brunei, and in Halmahera, Indonesia	N/A	0.111	N/A
Black tiger snake	Australia	0.099	0.131	N/A
Mainland tiger snake	Australia	0.118	0.118	0.014
Western Australian Tiger snake	Australia	0.124	0.194	N/A
Beaked sea snake	Tropical Indo-Pacific	0.164	0.1125	N/A

Note on Snakebite Deaths in Australia: Despite being home to many of the world’s most venomous snakes, Australia averages only about 2 deaths per year from snakebites, thanks to widespread availability of antivenom and modern medical care.

Australian Snakes Aren’t poisonous

It’s a common misnomer to refer to venomous snakes as poisonous. There is a distinct difference between venom and poison. Poisons need to be ingested, inhaled, or absorbed through the skin, whereas venom must be injected into the body via a mechanical action, such as a bite or sting. Interestingly, there exist a few snake species that are genuinely poisonous. For example, keelback snakes exhibit both venomous and poisonous characteristics. These reptiles store toxins in their nuchal glands, which they acquire by consuming toxic toads. Likewise, certain garter snakes found in Oregon have the ability to retain toxins within their livers after ingesting rough-skinned newts.

While the distinction may appear subtle, the term ‘venomous’ is used to describe organisms that deliver toxins directly into another organism’s body, whereas ‘poisonous’ refers to those that release toxins when touched or consumed. The keelback snake’s dual capability of being both venomous and poisonous exemplifies the extraordinary adaptability and survival strategies found in nature. This duality is not merely a trivial detail but a significant aspect of their biology and ecological interactions.