Are Australian Snakes Really That Deadly?

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Australia is renowned worldwide for our venomous and poisonous creatures, from snakes, spiders and ticks on land, to lethal jellyfish, stingrays and stonefish in our waters. Even the shy platypus can inflict excruciating pain if handled without due care.

Yet while injuries and deaths caused by venomous snakes and jellyfish are often sensationalised in the media, and feared by international visitors, a recent review found that very few “deadly” Australian animals actually cause deaths.

Between 2000 and 2013, there were two fatalities per year from snake bites across Australia, while the average for bee stings was 2.2 and for jellyfish 0.25, or one death every four years. For spiders – including our notorious redbacks and Sydney funnel-webs – the average was zero.

Snakes nevertheless strike fear into many people who live in or visit Australia. When we have a higher risk of injury or death from burns, horses, bee stings, drownings and car accidents, why don’t we fear these hazards as we do the sight of a snake?

Snakes and statistics through history

James Bray, Venomous and Non-Venomous Reptiles (1897). [Image: State Library of NSW/Peter Hobbins]

When settlers arrived in Australia in the late 18th century, they believed that Australian snakes were harmless. By 1805 it was accepted that local serpents might kill humans, but they were hardly feared in the same way as the American rattlesnake or Indian cobra.

Until the 1820s, less than one human death from snake bite was recorded each year; in 1827 visiting surgeon Peter Cunningham remarked that:

…comparatively few deaths [have] taken place from this cause since the foundation of the colony.

Similar observations were made into the 1840s. What the colonists did note, however, was the significant death toll among their “exotic” imported animals, from cats and sheep to highly valuable horses and oxen.

By the 1850s, living experiments in domestic creatures – especially chickens and dogs – were standard fare for travelling antidote sellers. Given the popularity of these public snake bite demonstrations, from the 1860s, doctors and naturalists also took to experimenting with captive animals. It was during this period that official statistics on deaths began to be collated across the Australian colonies.

One sample from 1864–74, for instance, reported an average of four snake bite deaths per year across Victoria, or one death per 175,000 colonists. In contrast, during the same period one in 6,000 Indians died from snake bites each year; little wonder that around the world, Australian snakes were considered trifling.

The 1890s represented a dramatic period of divergence, though. On one hand, statistical studies in 1882–92 suggested that on average, 11 people died annually from snake bite across Australia. Similar data compiled in Victoria led physician James Barrett to declare in 1892 that snakes posed “one of the most insignificant causes of death in our midst”. On the other hand, by 1895 standardised laboratory studies, aimed especially at producing an effective antivenom, saw a global recognition that Australian snake venoms were among the most potent in the world.

In Sydney, physiologist Charles Martin claimed that Australian tiger snake venom was as powerful as that of the cobra. In 1902, his collaborator Frank Tidswell ranked local tiger snake, brown snake and death adder venoms at the top of the global toxicity table.

Over the ensuing century, this paradox has remained: why do so few Australians die from snake bites when our serpents have the world’s most potent venoms? Why aren’t they more deadly?

Deadly fear

Scientific research has delivered ever-expanding knowledge about venoms, what they do, how they work, how they affect us clinically, and their comparative “potency” based on animal studies. In response we have introduced first aid measures, guidelines, effective clinical management and treatment, which in Australia forms one of the world’s best emergency health care systems.

In contrast, countries where snakebites cause far more deaths generally face challenges in accessing affordable essential medicines, prevention and education options.

Snakes form an essential part of their ecosystems. They do not “attack” humans, mostly being shy animals, but are defensive and prefer to escape.

It would seem that venom potency is not a good measure of deadliness, and it may be a combination of our history, behaviour and belief that creates a cultural fear.

Without understating the potential danger posed by venomous snakes, what we offer instead is reassurance. As nearly two centuries of statistics and clinical experience suggest, most snake bites in Australia are survivable, if managed quickly, calmly and effectively. In fact, encounters with humans all too often prove deadly to the snakes themselves – a paradox that is within our power to change.



Ronelle Welton, Scientist, University of Melbourne and Peter Hobbins, ARC DECRA Fellow, University of Sydney

This article was originally published on The Conversation.


Comments

    Not one mention of the lethality of the Hoop Snake, and what about the deadly Drop Bear?

    Surely, the number of Indian snakebite deaths is proportional to their population (both people and snakes) and exposure? Cobras are quite happy in urban environments, as are a number of the Australian poisonous snakes, but a large proportion of the poisonous Australian snakes are only found in the bush, in extremely unpopulated environments?

    (Excerpt from Douglas Adams' speech on the endangered Kakapo Parrot - this bit's about snakes. Whole transcript at http://nokyotsu.com/parrots/)

    There is in Melbourne a man who probably knows more about poisonous snakes than anyone else on earth. His name is Dr. Struan Sutherland, and he has devoted his entire life to a study of venom.

    “And I’m bored at talking about it,” he said when we went along to see him the next morning laden with tape recorders and notebooks. “Can’t stand all these poisonous creatures, all these snakes and insects and fish and things. Wretched things, biting everybody. And then people expect me to tell them what to do about it. I’ll tell them what to do. Don’t get bitten in the first place. (Laughter.) That’s the answer. I’ve had enough of telling people all the time. Hydroponics, now that’s interesting. (Laughter.) Talk to you all you like about hydroponics. Fascinating stuff, growing plants artificially in water, very interesting technique. We’ll need to know all about it if we’re going to go to Mars and places. Where did you say you were going?”

    “Komodo.”

    “Well don’t get bitten, that’s all I can say. (Laughter.) And don’t come running to me if you do because you won’t get here in time, (laughter) and anyway I’ve got enough on my plate. Look at this office, full of poisonous animals all over the place. See this tank, it’s full of fire ants. Venomous little creatures. What are we going to do about them? Anyway, I got some little fairy cakes in case you were hungry. Would you like some little cakes? I can’t remember where I put them. There’s some tea but it’s not very good. Anyway, sit down for heaven’s sake.

    “So, you’re going to Komodo. Well, I don’t know why you want to do that but I suppose you have your reasons. There are fifteen different types of snake on Komodo, and half of them are poisonous. The only potentially deadly ones are the Russell’s Viper, the Bamboo Viper and the Indian Cobra.

    “The Indian cobra is the fifteenth deadliest snake in the world, and all the other fourteen are here in Australia. (Laughter.) That’s why it’s so hard for me to find time to get on with my hydroponics, with all these snakes all over the place.

    “And spiders. The most poisonous spider is the Sydney funnel-web, we get about five hundred people a year bitten by spiders. A lot of them used to die, so I had to develop an antidote to stop people bothering me with it all the time. (Laughter.) Took us years. Then we developed this snake bite detector kit. Not that you need a kit to tell you when you’ve been bitten by a snake, (laughter) you usually know, but the kit is something that will detect what type you’ve been bitten by so you can treat it properly.

    “Would you like to see a kit? I’ve got a couple here in the venom fridge. Let’s have a look. Ah look, the cakes are in here too. (Laughter.) Quick, have one while they’re still fresh. Fairy cakes, I baked ’em myself”

    He handed round the snake venom detection kits and these home baked fairy cakes and retreated back to his desk, where he beamed at us cheerfully from behind his curly beard and bow tie. We admired the kits which were small efficient boxes neatly packed with tiny bottles, a pipette, a syringe, and a complicated set of instructions that I wouldn’t want to have to read for the first time in a panic. And then we asked him how many of the snakes he had been bitten by himself.

    “None of ’em,” he said. “Another area of expertise I’ve developed is that of getting other people to handle the dangerous animals. (Laughter.) Won’t do it myself. Don’t want to get bitten, do I? (Laughter.) You know what it says on my book jackets? ‘Hobbies: gardening, with gloves; (laughter) fishing, with boots; travelling, with care.’ That’s the answer. What else? Well in addition to the boots wear thick baggy trousers. And preferably have half a dozen people trampling along in front of you making as much noise as possible. (Laughter.) The snakes pick up the vibrations and get out of your way. Unless it’s a Death Adder, otherwise known as the Deaf Adder, (laughter) which just lies there. People can walk right past it and over it and nothing happens. I’ve heard of twelve people in a line walking over a Death Adder and the twelfth person accidentally trod on it and got bitten. Normally it’s quite safe to get twelve in line. You’re not eating your cakes. Come on, get them down you, there’s plenty more in the venom fridge.” (Laughter.)

    We asked, tentatively, if we could perhaps take a snake bite detector kit with us to Komodo.

    “Course you can, course you can. Take as many as you like. Won’t do you a blind bit of good because they’re only for Australian snakes.” (Laughter.)

    “So what do we do if we get bitten by something deadly, then?” I asked.

    He blinked at me as if I were stupid. (Laughter.)

    “Well what do you think you do?” he said. “You die of course. That’s what deadly means.” (Laughter.)

    “But what about cutting open the wound and sucking out the poison?” I asked.

    “Rather you than me,” he said. (Laughter.) “I wouldn’t want a mouthful of poison. Shouldn’t do you any harm, though, snake toxins are of high molecular weight so they wont penetrate the blood vessels in the mouth the way that alcohol or some drugs do. And then the poison gets destroyed by the acids in your stomach. But it’s not necessarily going to do much good either. I mean, you’re not likely to be able to get much of the poison out, but you’re probably going to make the wound a lot worse trying. And in a place like Komodo it means you’d quickly have a seriously infected wound to contend with well as a leg full of poison. Septicaemia, gangrene, you name it, it’ll kill you.”

    “What about a tourniquet?” I asked.

    “Well, fine if you don’t mind having your leg cut off afterwards. You’d have to because if you cut off the blood supply to it completely it will just die. And if you can find anyone in that part of Indonesia who you’d trust to take your leg off then you’re a braver man than me. (Laughter.) No, I’ll tell you, the only thing you can do is apply a pressure bandage direct to the wound and wrap the whole leg up tightly, but not too tightly. Slow the blood flow but don’t cut it off or you’ll lose the leg. Hold your leg, or whatever bit you’ve been bitten in, lower than your heart and your head. Keep very, very still, breathe slowly and get to a doctor immediately. (Laughter.) If you’re on Komodo that means a couple of days, by which time you’ll be well dead. (Laughter.)

    “Now, the only answer, and I mean this quite seriously, is don’t get bitten. There’s no reason why you should. Any of the snakes there will get out of your way well before you even see them. You don’t really need to worry about the snakes if you’re careful. No, the things you really need to worry about are the marine creatures.”

    “What?” (Laughter.)

    “Scorpion fish, stonefish, sea snakes. Much more poisonous than anything on land. Get stung by a stonefish and the pain alone will kill you. People drown themselves just to stop the pain.” (Laughter.)

    “Where are all these things?”

    “Oh, just in the sea. Tons of them. I wouldn’t go near it if I were you. Full of poisonous animals. Hate them.” (Laughter.)

    “Is there anything you do like?”

    “Yes. Hydroponics.”

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