The Seven Deadliest Australian Animals

June 8, 2009— -- As a scientist and an adventurer in the wild, Brady Barr often comes face-to-face with some of nature's most dangerous creatures. And now he's taking on Australia, home to many of the world's most venomous animals.

One bite from some of these beasts, and there's no chance of recovery, but that didn't stop Barr, of the National Geographic show "Dangerous Encounters With Brady Barr," from giving "GMA" a first-hand look at Australia's deadliest creatures.

"I've got this thirst for knowledge," Barr told "Good Morning America." "I mean, when do you ever get to see a platypus? ... You rely on guys like me to give you that up close and personal look so you can find out more about these amazing creatures. They are deadly but fascinating."

Barr created a list of the most deadly Australian animals based on a combination of four categories: venom, attitude, chance of contact, and death toll.

Why are there so many dangerous animals in Australia?

"That is a really good question," Barr said. "There are a lot of theories. One hypothesis is it's an isolated place. A really harsh place to live and you better be tough. You better be harsh if you're going to survive."

Find out more about these amazing animals below and watch the "Dangerous Encounters: Deadly Australia" when it premieres Saturday, June 20, 2009 at 10 p.m.

To learn more about Australia's animals, visit the Australian Museum.

Stonefish

Possibly the deadliest fish in the world, the stonefish gets its name from its ability to camouflage itself in a rocky sea environment.

The stonefish feeds on smaller fish and shrimps, but its deadly sting is not used for catching prey. Thirteen venomous spines projecting along its back offer protection from sharks, rays, and other creatures that might think of having the stone fish for dinner.

When these spines feel pressure from a gulping mouth or a stepping foot, a highly toxic venom is involuntarily expelled into the unwitting victim. The sting causes terrible pain and can result in death if not treated.

Duck-Billed Platypus

With its duck bill and webbed feet, the platypus might look funny, but the world's only venomous furred animal is no joke. A male duck-billed platypus has a poisonous spur on his hind legs. The potent defense mechanism is curious as the platypus had no natural predators.

When a platypus feels threatened, it will throw venom out of this spur on to the intruder. The venom from a platypus sting isn't likely to kill, but the pain is excruciating and there is no way to stop it.

The platypus lives in Australia's rivers and banks, feeding on shrimp, insects, and other river-dwellers.

Deadly Australia: More Dangerous Animals

Blue Ringed Octopus

Found only in the waters of southern Australia, the blue ringed octopus is beautiful, but deadly. A little over 5 inches in length, it is named for the florescent blue rings that appear as a warning when the cephalopod is agitated.

The tiny octopus uses its poison, secreted from two separate glands, for hunting and self-defense. It uses one poison to kill crabs and shrimp before it consumes them. The other poison is fatal and causes almost instant paralysis. The little octopus will generally swim away and is only likely to sting a human if it is stepped on.

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.

Sea Snake

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.

Box Jellyfish

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.

Deadly Australia: More Dangerous Animals

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.