Box Jellyfish (Chironex Fleckeri)
The Box Jellyfish is notorious for its extremely potent venom. Each tentacle is loaded with over 500,000 Cnidocytes, little harpoon-shaped needles that carry the venom. Box jellyfish are easily recognized; as their name would imply, their hood (body) is a box shape. Box Jellyfish are also the only jellyfish to have eyes. They can’t see as well as other fish or mammals but they can follow simple lights, guiding them even in darker water. Unlike other jellyfish who have small and simple nervous systems allowing them to control slight movements, Box Jellyfish have developed a full nervous system ring near the bottom of their hood (body), allowing for more control over their movement. Spending most of their time slowly gliding through the water, Box Jellyfish will not attack without being provoked, either by another animal or human. The Box Jellyfish has picked up a few nicknames: ‘the sea wasp’ and ‘marine stinger’ are most commonly used. The Box Jellyfish have developed the venom carried in their tentacles so when they can catch larger prey, there is less of a struggle and less chance the Box Jellyfish will get hurt, either from a bite, or the in case of a crab, a pinch.
Salt Water Crocodile (Crocodylas Porosus)
These 900 kg, 6 m predators (with females being smaller) are covered in less armored plates than a normal alligator or crocodile, but are adapted to sleeping underwater rather than on land. Preying on pretty much anything that causes a threat, including sharks, when taking down a large animal such as a buffalo, crocodiles will ‘death roll’: a move designed to not only drown the prey animal but also break its neck. Salt Water Crocs are often mistaken for alligators due to their much broader body, rather than the leaner body crocodiles normally have. Spending most of their time in fresh swamp waters and reaching up to 16 mph in short bursts, Salt Water Crocodiles generally swim at around 2 mph to conserve energy for any larger prey that may pass.
Blue-Ringed Octopus (Hapalochlaena)
Easily distinguished from other octopi due to their wonderfully vibrant blue and black rings and yellow body, the Blue-Ringed Octopus is also one of the most venomous animals living in Australian waters. Feeding on shrimps, small fish and even crabs, Blue-Ringed octopi pounces on their prey, much like a cat with a ball of string, then release potent venom after the first bite. The venom is called Tetrodotoxin, which cause paralysis and respiratory arrest. Within minutes this will lead to cardiac arrest. No anti-venom is available for humans, however, treatment can be given, such as squeezing the venom out of the wound. With a body size of 8 inches, Blue Ringed octopi can hide in small cracks waiting for prey or possible male or females to pass by. Blue-Ringed octopi have Chromatophore Cells, these help them to camouflage themselves until they are provoked. When deep-sea diving or snorkeling, if you spot one of these magnificent creatures don’t be tempted to get closer, just admire their colouration and movement from a safe distance.
King Brown Snake (Pseudechis Australis)
The King Brown Snake is one of the longest venomous snakes in the world and the second largest snake in Australia (the first being the Amethyst Python, reaching a staggering 9 m in length) reaching 3 m in length and are a beautiful rich-brown colour, with some being almost black in colour. With a robust body and a wide head, King Browns prey on lizards, birds, mammals and even other snakes, both constrictors and venomous. Habituating in grass and desert areas, Kings Browns will shelter under sand, rocks and even rubbish piles - don’t let the size fool you - King Browns can curl up and hide pretty much anywhere waiting for prey and end up accidentally bite a human on the leg or foot. The King Brown is capable of delivering a massive 100 mg of venom in a single bite.
Funnel Web Spider (Atrax robustus)
The Funnel Web Spider is know throughout Australia and is feared by people due to the high potency of the venom and the fact they can hide anywhere from sheds to toilets, having a body length of only 2 - 7 cm. Even with the high potency of the Funnel Web’s venom people can and have survived (for instance, this story about a 94-year old grandmother who has survived two bites: http://current.com/129tm4c). The body of the Funnel Web ranges from a blue and black coloration to brown and even a plum colour. As with most arachnids the female is not only significantly larger than the male, but also lives longer. Funnel Webs like to stay in the comfort of their silk-lined burrows generally waiting for prey such as insects, mice and lizards to come to them. Using the fine hairs on their legs and body Funnel Webs can stay underwater for up to 24 hours. Using the tiny pockets of air collected on the hair on their bodies they can keep breathing, unlike most arachnids who would drown, even after being submerged. Provoking the Funnel Web will lead to a bite. Remember, when a spider raises up its four front legs with its fangs showing, back away, don’t be stupid and try to get close. Funnel Web burrows are easily spotted: they are enclosed burrows with web lining around the front of the entrance and a piece of bark or leaves will be near by - this is the door the Funnel Web will pop out from to catch unsuspecting prey.