They have a life span of about two years. The male blue ringed octopus dies after mating. The female will lay and tend to about 50 eggs, during which time she will not eat. After the new eggs hatch, the female blue ringed octopus will die.
There are many species of sea snake. According to the Cooperative Research Centre for the Great Barrier Reef, they have flat tails that help them swim and although they look like eels, sea snakes breathe air through their nostrils and don't have gill slits.
The scaly snakes slither through tropical waters and can stay submerged for long periods of time due to a lung that extends for almost the entire length of their body and their ability to breathe through their skin.
The sea snake is able to control the amount of venom released when it bites. And a bite might seem less serious as it takes about 30 minutes for its effects to be felt. Muscle stiffness, jaw spasms and pain come before blurred vision and respiratory paralysis.
This pale blue jellyfish is beautifully hypnotic to watch but dangerous to the touch. It gets its name from the four distinct sides of its bell-shaped body.
According to the Australian Institute of Marine Science, the box jellyfish has about 15 tentacles – each with thousands of stinging cells. They eat small fish and crustaceans. Their very potent venom kills their prey instantly.
Unless treated immediately, there is little chance of survival once stung by the box jellyfish and the pain from a sting is agonizing, so intense that a victim will probably go into shock and be unable to swim to safety. A box jellyfish attack can cause cardiac arrest and nerve damage within minutes.
Eastern Brown Snake
The eastern brown snake, found in mainland Australia, is the second most venomous snake in the world. Its venom is paired with an extremely aggressive nature. Despite its name, the eastern brown snake can be tan to dark brown, orange or black, with a cream or white belly.
They eat lizards, frogs, and small mammals using a method of constriction and poison. They are incredibly fast and when provoked, attack repeatedly.
An eastern brown snake's venom is extremely poisonous and because the venom contains toxins that interfere with blood clotting, a bite puts a victim at risk of major bleeding.
Sydney Funnel Web Spider
The Sydney funnel spider is shiny, dark, and deadly. If threatened, the Sydney funnel web spider will show his fangs. What is most dangerous about this spider is its environment: the deadly arachnid is often found in urban areas.
Barr called this spider "your worst nightmare."
Sydney funnel spiders are known to wander into homes, backyards, and swimming pools in the summer and autumn while looking for females to mate with.
"The thing that I find terrifying about this spider is it gets you where you feel safe, in your house," Barr said. "You're afraid of sharks, don't go into the sea. You're afraid of snakes, don't pick them up. This guy comes into your house and gets you in your bed, in your kitchen, in your bathroom. That's what's terrifying about this guy."
Their venom is one of the most toxic of any spider, and contains a neurotoxin that attacks the human nervous system and is extremely lethal. However, since the introduction of anitvenom in 1984, there have been no fatalities.