How Australia's King Brown Snake Got Its Name

By: Desiree Bowie  | 
Reddish snake on reddish sand with rocks in the background.
The king brown snake enjoys sandy deserts — the drier the area, the better — and thrives in arid regions of central, northern, and western Australia. Kristian Bell / Getty Images

The king brown snake is a venomous predator with various behaviors adapted for hunting, defense and reproduction. Their climbing ability, feeding habits and territorial tendencies make them unique among snake species in Australia, where they've carved out a serious reputation as one of the most dangerous serpents in the country.

Despite their large size and venomous nature, king browns are not typically aggressive toward humans unless they feel provoked or threatened. But how did this humble black snake species acquire such a regal name?


Let's find out.

The King Brown's Scientific Name and Nickname

The king brown snake, scientifically known as Pseudechis australis, belongs to the Elapidae family, which includes venomous snakes like cobras and mambas. This species is part of the black snake genus Pseudechis and is known for its potent venom and robust build.

The name "king brown" comes from its large size and brownish hue, but the species is actually more closely related to black snakes than brown snakes (genus Pseudonaja). Despite this, the name has persisted in popular usage.


The species' other common name, mulga snake, is derived from its frequent presence in mulga habitats. Mulga is a small tree or shrub from the Acacia aneura, native to Australia. It is particularly widespread in arid and semi-arid regions.

This plant forms part of the distinctive woodland ecosystem known as mulga woodlands, characterized by dense, low-lying vegetation, which offers mulga snakes shelter and an abundance of prey.


How Big Are King Brown Snakes?

King browns rank among the larger snake species in Australia; they typically measure around 8 feet (about 2.5 meters) in length, but some can grow to nearly 10 feet (3 meters), the maximum recorded length.

That said, their size can vary based on their geographic location and the environmental conditions of their habitat. Snakes in more arid regions are often larger than those in temperate areas.


Young king browns, also known as juveniles, are considerably smaller than their mature adult counterparts. When they hatch from their eggs, they are pretty small, typically measuring around 9 inches (22.9 centimeters) in length. As they grow, the species undergoes a significant growth spurt.

They continue to feed on small prey items, such as insects and small reptiles, which provides them with the necessary nutrients to develop and increase in size. It usually takes several years for them to reach their full adult size.


Physical Features

The mulga snake possesses several distinctive physical features. Like many other snake species, this serpent has specialized heat-sensing pits on its smooth snout. These pits help them detect warm-blooded animals by picking up faint infrared radiation emitted by their bodies, which aids them in hunting for food, particularly at night.

They also have flexible jaws, which allow them to consume prey much larger than their head by unhinging their lower jaw and stretching their mouth around their meal. This ability is crucial for their survival, given the size and variety of the prey they consume.


The snakes are ectothermic, often called "cold-blooded," which means they cannot internally regulate their body temperature and instead depend on external environmental conditions to manage their body heat.

These dangerous snakes bask in the sun to warm up and seek shade or burrows to cool down. A particularly remarkable feature is its resistance to the venom of other snakes. This adaptation allows the robust snake to prey on and consume other venomous snakes without suffering the toxic effects that would be lethal to most other creatures.


Geographic Range

Some snakes must live near streams and other bodies of water, but the king brown enjoys sandy deserts — the drier the area, the better.

That's why they thrive throughout the deserts and arid regions of central, northern and western Australia — their native range. The snake is prevalent in the Northern Territory and also found in the arid and semi-arid regions of South Australia, as well as central and western Queensland.


Further south, in New South Wales, the snake is found in the western and southern areas of the state, and its range extends into the northwestern parts of Victoria.

The king brown is highly adaptable and can live comfortably in grasslands, scrublands and woodlands. This adaptability even allows it to thrive in areas impacted by human activities. However, its presence diminishes in the cooler southern regions of Australia, and it is notably absent from the island of Tasmania.


Is the King Brown Snake Venomous?

Yes, the king brown is one of the most venomous snakes in Australia and is known for its potent venom. While its venom is highly toxic, it is less lethal than other Australian snakes, like the inland taipan or eastern brown snake.

The venom of the king brown snake contains a complex mixture of toxins, including myotoxins, coagulants and neurotoxins. These components can cause various symptoms in humans, such as pain, swelling, blood clotting disorders, muscle damage and even renal failure.


Despite its venomous nature, the king brown snake is not generally aggressive and avoids confrontation with humans. Most bites occur when the snake is provoked or accidentally stepped on. As with all wildlife, especially venomous species, it's essential to exercise caution and respect their space to avoid potential danger.

Is a King Brown Snake Bite Lethal?

Fatalities from a king brown snake bite are rare, especially with the availability of effective black snake antivenom and prompt medical treatment.


Hunting Behaviors

This venomous snake is a skilled hunter, employing venom and constriction to subdue their prey. They primarily hunt using a sit-and-wait or ambush strategy, often lying in wait for their prey.

Once a suitable option comes within range, they strike quickly, using their potent venom to immobilize and subdue the prey. After envenomation, the snake will consume its prey whole.


The venom of the king brown is not only a defense mechanism but also an essential tool for overcoming prey, especially when dealing with other snakes or larger mammals.

Feeding and Diet

The Australian snake has a varied and opportunistic diet primarily composed of other reptiles and reptile eggs. This includes a range of lizards and other snakes — including their own species — demonstrating their apparent immunity to snake venom.

Their diet also extends to small mammals, particularly rodents, which they hunt and consume, contributing to controlling rodent populations in their habitats. Additionally, they occasionally prey on birds, bird eggs and frogs.


The Aussie snakes have been observed feeding both during the day and at night, indicating flexibility in their feeding habits. Their diet and consumption patterns play a crucial role in the ecological balance, as they help manage populations of their prey species and, in turn, are preyed upon by larger predators, contributing to the food chain in their ecosystems.

Breeding and Mating Habits

The breeding season for the large king brown snake depends on where it lives. In southwestern Australia, mating typically occurs in early spring; in the Eyre Peninsula, it's observed in mid-spring. In northern populations, breeding might not follow a fixed seasonal pattern and could be influenced by environmental factors like the wet and post-wet seasons.

During the mating season, males engage in ritual combat to establish dominance and win the right to mate with a female. This involves intertwining their bodies and attempting to push over their opponent. After a successful courtship, the female then mates with the dominant male.


After mating, females lay eggs (typically 39 to 42 days later), producing clutches of around four to 19 eggs, with larger females often laying more. The eggs incubate for about 70 to 100 days, depending on the temperature. In rare cases, two hatchlings might emerge from one egg.

After hatching, the young snakes are independent and start fending for themselves. Their growth rate is rapid, and they mature into adults capable of reproduction within a few years.


Predators and Diseases

King browns are vulnerable to various natural predators, particularly in their juvenile stages. Birds of prey, such as eagles and hawks, are significant threats, as they use their aerial advantage to spot and capture young snakes.

Mammalian predators — including dingoes, feral cats and wild pigs — also prey on these mulgas. Their ability to hunt on the ground and in burrows makes them effective predators of young and sometimes adult snakes.


Larger reptiles, including monitor lizards and even other giant snakes, can also be predators of the king brown, especially targeting the juveniles. These reptilian predators are well-adapted to hunting in similar habitats and can pose a considerable threat.

Health Issues

Regarding diseases, these black snakes are susceptible to various health issues. Parasitic infections are common; they can be afflicted by internal parasites like worms, which impact their digestive system, and external parasites such as ticks and mites, which can affect their skin and overall health.

Respiratory infections are a concern, especially in environments with poor ventilation, which can occur in captive situations. Bacterial and fungal skin infections can arise from injuries or unsanitary conditions, leading to further health complications.

In captivity, nutritional deficiencies are a notable issue. An improper diet can lead to metabolic disorders, impacting the snake's growth, immune system, and overall health.

Stress-related diseases are also a concern in captive snakes, caused by improper handling, inadequate enclosure conditions and exposure to extreme temperatures.

This article was written in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.