Outdoor

Saltwater crocodiles are one of the most dangerous animals in Australia. (Credit: Getty images)

Australia's most dangerous predators

  • BY Chris Ord |
  • May 14, 2012

We've got the experts' advice on how to avoid Australia's top predators and what to do if you fall victim.

IT'S ALL VERY WELL to spend millions of dollars on Oprah Winfrey spruiking our wide, open spaces, but watch that publicity lose its gloss when actor Sam Worthington brings up the subject of Australia's dangerous creatures on The Late Show with Dave Letterman.

Letterman: "Can you just go out and play?
I mean it's dangerous in Australia."
Worthington: "You're aware of the dangerous animals. We have dugites...which is like one of the most poisonous snakes in the world...and if it bites you, you have 10 seconds...You have redback spiders; same thing, if it bites you, you have 10 seconds."
Letterman: "So what's a person to do?"
Worthington: "Pray."

Which is exactly what Tourism Australia did when their media monitors caught wind of The Late Show interview: prayed that no-one was watching. Three and a half million isn't many, is it?

And that's the problem with the rep garnered by Australia's creepy crawlies: yes we have some of the world's most dangerous, but like Worthington's most famous effort, Avatar, they're also unfairly maligned if you consider the context. In general, Avatar didn't harm anyone and for the most part neither do the creatures in our bush. It doesn't help that the likes of Worthington (along with a legion of Poms and Kiwis) tend to blow things out of all proportion. I mean, honestly: a dugite (a type of brown snake found only in the south of Western Australia) while dangerous does not kill in 10 seconds. If it did, the seven year-old Perth boy who was bitten after a dugite crawled into his bedroom and wrapped around his arm while he slept, would not be alive. After seeking medical attention quickly, he made a full recovery.

And a red-back spider? From the Australian Venom Research Unit at the University of Melbourne: "Red-back spider bite is thought to be the commonest serious spider bite in Australia, particularly over the summer months. An antivenom was introduced in 1955 and no deaths attributed to treated redback spider bites have been reported since."

Then there's the online hysteria, an entry after a list of the world's deadliest snakes reading: "Everything in Australia wants us dead, and everything has the capability to make that a reality. (Ianz09)" That reality, Ianz09, is about as plausible as Avatar. Still, there are a few creatures lurking in Australia's wild places that, wrong time, wrong place, can cause, as the Monty Python crew would say, "just a flesh wound", or so. Okay, so it's a flesh wound you may want to get to the hospital in a hurry to treat, but it won't necessarily  kill you as quickly as Hollywood would have you believe. Unless it's a crocodile. They'll kill you quite quickly, actually.

Here are the top five most dangerous animals in Australia:

FUNNEL-WEB SPIDER

(Atracinae)
A bite from this highly venomous spider can kill a human in two hours, with a toxic cocktail that switches on all your nerves at once.

While no-one has died from a funnel-web bite for more than 30 years, the spider remains a creature that raises hairs on the back of everyone's neck. The Australian Venom Research Unit's Dr Ken Winkel reckons the funnel-web is peerless, worldwide, in terms of how venomous it is.

"No other spider can kill an adult in two hours," he says of the funnel web, which is a spider of ancient classification, more primitive than most. "They are a black and hairy, an almost demonic-looking spider - so they don't do themselves any favours in the likeability stakes. And they are aggressive, especially the males in the summer looking for a mate."

Ranging from 1-5cm, funnel-web spiders live in burrows in the ground, or in stumps, tree trunks or ferns. What most people think of as a funnel web is actually a collection of about 35 different species, many of which are dangerous. The Sydney funnel-webs, Atraxrobustus, garners the most attention. They carry a very powerful neurotoxin which can be administered in large doses - hence they get a particularly bad reputation and are responsible for 13 of Australia's 27 recorded deaths from spider bites in the past 100 years. "But there are other species of funnel-webs that can cause trouble," says Ken. "Particularly the tree-dwelling variety in northern NSW where the female is as dangerous as the Sydney funnel-web." There is also a variety that lives around the Sunshine Coast and Gold Coast hinterland whose venom, while not as bad as its Sydney cousin, can still cause serious illness.

A funnel-web's venom is packed with at least 40 different toxic proteins (called peptides). Only one, robustoxin, is really dangerous to humans. Like snake neurotoxins, robustoxin disrupts nerve signals, but in the opposite way. Instead of shutting down nerve signals, it switches them all on at once, causing massive electrical overload in the body's nervous system. The protein attaches itself to nerve synapses and prevents them from switching off - salivary glands, tear ducts and sweat glands all run uncontrollably, muscles begin to spasm, blood pressure climbs as vessels contract and then falls to dangerously low levels. Most fatalities occur from either cardiac arrest or a pulmonary oedema, where the capillaries around the lungs begin to leak and the patient effectively drowns.

As with with snakebite, first aid for a funnel-web envenomation is pressure-immobilisation while ensuring breathing and circulation are maintained along with urgent hospitalisation.

DISTRIBUTION: The Sydney funnel-web spider is found within 100km of the city. In the tropics and subtropics, they favour rainforests and higher altitudes, but in southern states they live in drier eucalypt forests and woodlands, as well as snow country.
HOW AND WHERE IT'LL STRIKE: Keep your hands out of deep, dark places. Get to hospital quickly if you're fanged and apart from a case of arachnophobia, you'll live.
NUMBER OF DEATHS: Nobody in Australia has died from a spider bite since 1980 after the successful introduction of antivenom for all native species.
DID YOU KNOW? Not all creatures are affected by funnel-web poison: mice, rabbits, guineapigs, dogs and cats are relatively immune and often survive 100 times the lethal human dosage. In general the male is five times more dangerous than the female.


BLUE-RINGED OCTOPUS

(Hapalochlaena maculosa, h. lunulata)
Tiny it may be, but this octopus can cause serious damage. With a painless sting, you won't even know you've been bitten.

"The blue-ringed octopus represents a double-edged sword," says Ken. "They are uncommon, reclusive, and don't like human activity." So pretty harmless, then? "Well, you need to work hard to be bitten. The last-recorded fatalities were instances where humans proactively interacted with the creature. That said, I know of a tourist recently who picked up a shell, put it in his pocket and there was a blue-ringed octopus inside, which bit him - they are quite small, smaller than you'd think."

Under 12cm as a matter of fact, and its body is the size of a golf ball. They live in reef flats and tidal pools, secrete themselves in rocks and in crevices and, as in this case, have a habit of squatting in dead shells and discarded cans. The tourist in question got a nasty fright - through its salivary glands the blue-ringed octopus administers a powerful nerve toxin called tetrodotoxin, which causes a paralysing effect within 10 minutes. There is no antivenom.

"If you happen to be by yourself you may be in trouble," says Ken. "But if someone is with you and knows to support your respiration - CPR if necessary - and you seek medical help urgently, then you will live." As with snakebites, pressure-immobilisation is recommended for blue-ringed octopus envenomation. And just because you can't see blue rings flashing at you from the rockpool, don't think that it's not a blue-ringed: the creature's usual colour is a mottled brown. The bright, blue rings appear on its skin only when it is threatened (and thus you are in some danger of a bite).

If you do get bitten, it won't be painful and may go unnoticed. But the toxin acts quickly and symptoms include weakness, numbness around the face, nausea and vomiting. Death may occur in as little as 30 minutes, especially in the vulnerable (children, the elderly, or people with heart and other health conditions).

DISTRIBUTION: Entire Australian coastline in warm, shallow waters.
HOW AND WHERE IT'LL STRIKE: Keep your hands and feet out of small, underwater crevices.
NUMBER OF DEATHS: It has only been attributed with causing three known deaths. There have been no deaths since the 1960s and hospital admissions are exceedingly uncommon.
DID YOU KNOW? The blue-ringed octopus has blue blood, three hearts and enough poison to kill 26 humans. The same nerve toxins injected by a blue-ring are found in the flesh of fugu fish - a pricey delicacy beloved by the Japanese. The ingestion of fugu that's not been expertly prepared leads to more hospitalisations than blue-ringed octopus bite.


IRUKANDJI & AUSTRALIAN BOX JELLYFISH

(Carukia barnesi, malo kingi and chironex fleckeri)
It's searingly hot and all you want to do is cool off in the ocean...but beware the deadly, silent and invisible killers lurking under tropical waters.

The Irukandji jellyfish is oft quoted as the most dangerous jellyfish, perhaps because less is known about it. It is highly poisonous and is also an unseen menace, being a tiny, translucent 1-2cm diameter bell. No wonder the Irukandji people, near Cairns, didn't know it was the jellyfish causing a mysterious illness among their people.

The Irukandji's four stinging tentacles trail up to 30cm behind them. Get stung by them and you can develop what is known as 'Irukandji syndrome'. The sting site itself is only moderately painful, with little tissue damage, but approximately 30 minutes later, a victim develops symptoms, including severe back and abdominal pain, limb or joint pain, nausea, vomiting, profuse sweating and agitation. They may also experience numbness or paraesthesia - a sensation of tingling, burning, or pricking of the skin - and psychological phenomena such as a feeling of impending doom. Victims often require hospitalisation and serious painkillers and intravenous narcotics.

Despite the Irukandji's reputation for causing illness, Ken rates the box jellyfish - a related but different grouping - as "undoubtably the most dangerous in the world". It has been labelled as "the most lethal creature known to mankind"."We still have a fatality every year or two from the box jelly," Ken says. "In terms of creatures with the ability to kill quickly - a couple of minutes - it is almost peerless."

The box's lethality resides in its ability to deliver a significant amount of venom via hundreds of thousands of injections at once. "The Irukandji has four tentacles, one on each corner, whereas the box has up to 15 tentacles coming from each corner. That's up to 60 tentacles all with millions of injection harpoons filled with venom."

First-aid for box jellyfish stings involves pouring vinegar over the site, removing tentacles and taking painkillers; however, the vinegar does not remedy the poison already injected. The result of a sting is severe localised pain, often associated with vigorous attempts by the patient to remove the tentacles, confusion, agitation, unconsciousness with respiratory failure and/or cardiac arrest. Due to the rapidity of onset of symptoms, immediate first-aid is  vital and cardiopulmonary resuscitation may be required.

DISTRIBUTION: Box jellyfish prefers to be near the coast, whereas Irukandji species tend to be both close to shore as well as further offshore, including near offshore reefs. They are both found near South East Asia.
HOW AND WHERE IT'LL STRIKE: Both jellyfish have tentacles that are generally invisible, can entangle you and have millions of harpoons that inject a lot of venom at once. The box jellyfish in particular is the only one on this list that can kill in minutes. Ergo, highly dangerous.
NUMBER OF DEATHS: Jellyfish account for more than 80 known deaths since 1883. The box jellyfish was responsible for 79 deaths, and Irukandji the other two.
DID YOU KNOW: Named after the Irukandji people, the Irukandji was first identified in 1961 by Dr Jack Barnes who, in order to prove it was the cause of so-called Irukandji syndrome (named in 1952), he captured the tiny jelly and allowed it to sting himself, his son, and a lifeguard.

 

INLAND TAIPAN

(Oxyuranus microlepidotus)
Get fanged by one of these guys and you're in for a bumpy ride: this snake has the most toxic venom of any land snake in the world.

When it comes to boasts, this one takes the cake: the biggest yield recorded for one bite was 110mg - that's enough to kill 100 humans. If you get envenomated, you're in for a bumpy ride. The venom has a neurotoxin that immobilises by paralysis, the poison binding to nerve endings, blocking electrical activity and shutting down communication between the brain and muscles. You'll experience headaches, nausea, vomiting, stomach pain, blurred vision and dizziness, sometimes accompanied by convulsions and, in severe cases, coma.

The neurotoxin is also a myotoxin, meaning it eats away at muscle tissue. Your urine may turn reddish-brown as muscles dissolve and are passed through your kidneys. In turn they are badly damaged by filtering so much tissue debris out of your blood, and kidney failure is a common complication and cause of death. Internal bleeding is the other major complication. The snake's second main toxin is a anticoagulant, which prevents blood-clotting by removing the body's supply of its natural blood-clotting agent, fibrinogen. This causes persistent bleeding from the bite site and can lead to more serious - sometimes fatal - internal haemorrhaging, especially in the brain.

Though it could potentially kill an adult human within 45 minutes, the inland taipan is not particularly aggressive and, with no known fatalities, and the only known bites being inflicted upon snake handlers effectively looking for trouble, you could say they present less of a threat than other snakes.

Dr Ken Winkel from the Australian Venomous Research Unit at the University of Melbourne, rates the brown snake as Australia's most dangerous based on the combined factors of venom toxicity (highly toxic), temperament (more 'nervous' than the inland taipan), distribution (widespread across mainland Australia) and likelihood of encounter given their diverse habitat (higher). "The brown snake - considered the second-most venomous land snake in the world - is much more nervous and more likely to strike," says Ken. "While there are no known deaths from the inland taipan, every year there is death by a brown because it is more widely distributed and it doesn't mind urban and farm areas."

Of all Australian snakes, the brown is responsible for the most carnage. "Of the average 500 to 600 annual admissions to hospital attributed to snakebites, 50 per cent can be attributed to browns," Ken says. He points out that Victorians do have more trouble with the tiger snake, which accounts for more hospitalisations in that state than the brown. Even so, Australia-wide there are only about 2-4 deaths a year as a long-term average over the past 30 years for all snakebites.

DISTRIBUTION: There have been sightings in northern NSW and in northern SA so the true range is unknown.
HOW AND WHERE IT'LL STRIKE: You're unlikely to encounter it, unless you're a desert dweller. But if you do, and it bites, you're in strife.
NUMBER OF DEATHS:  All recorded bites to date have been to snake handlers and no deaths have been documented.
DID YOU KNOW?  If the situation is handled calmly, it can take hours before a serious paralysing effect presents in an adult bitten by a taipan or other venomous Australian snake. Using immobilisation and bandage pressure, you can buy yourself hours, if not days to get assistance. It is better to stay put and send for a chopper than try to walk out of the bush when bitten.


SALTWATER CROCODILE

(Crocodylus porosus)
Regarded as one of nature's most effective killing machines, you don't stand a chance if a hungry saltie takes a liking to you.

The salty has reason to look so smug as it eyes you off from the riverbank: it is the world's largest reptile and regarded as one of nature's most effective killing machines. Most salty attacks occur between late September and January when crocodiles are hungry after the dry season and are preparing to breed. On land they are fast (faster than a horse over short distances) and in the water you won't know they are there until you're cuddling one as you succumb to its signature 'death roll'.

When they strike a large animal (like us), crocodiles usually grab a head or limb and then roll you into the water, generally breaking your neck or drowning you, so they can then dismember you into manageable bite-sized chunks. Their immensely powerful jaws will easily crush your bones. "Holding a 5 kilogram croc around the neck is hard when it really starts to struggle. With a much larger animal (say 500 kilograms) you have little chance," says Professor Grahame Webb, Australia's leading expert on crocodiles and chief of Crocodylus Park, a crocodile research and education centre in Darwin. Grahame reckons salties deserve their fearsome reputation. "Those who sugar-coat salties and the danger they present are doing themselves, the public and crocodiles in general a great disservice," he says. "Dive into a river in their territory and there is 100 per cent probability you will be taken. Salties are a serious predator."

Salties are also smarter than your average bear. Croc researcher Dr Adam Britton says that while crocodilian brains are much smaller than those of mammals (as low as 0.05 per cent of body weight in the saltwater crocodile), they are capable of learning difficult tasks with little conditioning. He suggests that saltwater crocodiles learn faster than lab rats and can track the migratory routes of prey as seasons change.

Stay away from attack zones: Mangrove swamps, waterways and riverbanks are all favourites. If your adventures necessarily take you to such places, he suggests remaining in something safe like your 4WD or a sturdy boat.

He adds a warning: "Don't let alcohol dampen the resolve to not go swimming in areas where there are salties, especially at night."

DISTRIBUTION: Found in coastal-river systems, coastal areas, some offshore islands and in some cases hundreds of kilometres from salt water. Protected since 1974, numbers have recovered almost back to pre-colonial populations.
HOW AND WHERE IT'LL STRIKE: If you enter their domain without regard, extremely high. If it's at night and you're drunk, pretty much a certainty you'll be doing the death roll mambo with one.
NUMBER OF DEATHS: 1-2 known deaths per year, usually highly publicised due to their viciousness and aggression. 4-10 non-fatal attacks per year.
DID YOU KNOW? The longest croc ever measured and verified was 6.4m (21ft). It could have weighed more than 1000kg. In Australia, there are unverified reports of crocs up to 8m.

 

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