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Venom - it's a cocktail of virulent biological toxins causing searing pain in seconds. It is the weapon of choice for thousands of species, but which one is most deadly to man? Of the creatures armed with this lethal cocktail, which is more likely to kill you?
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00:02It's one of nature's most efficient ways to kill.
00:07Once injected into the bloodstream, it can damage nerves and flesh in minutes
00:11and trigger searing pain in seconds.
00:15This is venom, a virulent biological toxin
00:19and a weapon of choice for thousands of species.
00:23But which one is most deadly to man?
00:26Of those creatures armed with this lethal cocktail,
00:30which is more likely to kill you?
00:36Among the world's venomous creatures, there are those whose reputations are infamous,
00:40but there are many less well-known killers out there.
00:47Everything from mollusks to fish may be armed with on-board biological weapons
00:51that are 100% natural and in many cases deadly.
00:59But when it comes to human beings, there's always been a great deal of debate
01:03as to which of these creatures presents the greatest threat.
01:09It has inspired one man to come up with a pioneering new system
01:13for ranking the world's most dangerous venoms.
01:17Dr Jamie Seymour is a venom biologist at James Cook University in Queensland, Australia.
01:27We want to take the terrestrial snakes, we want to take the marine snakes,
01:31we want to take the marine animals, we want to take the whole lot,
01:33bring them all together and test that venom drop for drop.
01:36And then we want to put in things like how aggressive the animals are
01:40and what their population distribution is.
01:42This ranking system allows Jamie Seymour to understand the different threats
01:47posed by venomous creatures and ultimately to identify measures for minimising the risks.
01:54It consists of five categories.
01:57The first is opportunity, or how likely is it that a creature will have the chance to bite.
02:03Those venomous creatures living in heavily populated areas will score far higher.
02:11Next comes aggression.
02:12We're more likely to become victims of aggressive rather than shy species.
02:18Then there's the injection mechanism.
02:20How well does the animal deliver its venom?
02:24Related to this is quantity.
02:26In short, the amount of venom delivered in a single bite or sting.
02:31Last, but not least, is potency.
02:35Just how toxic is the venom?
02:37Drop for deadly drop.
02:41Considering these five factors together is a brand new approach.
02:47And that'll allow us to compare, for the first time ever,
02:50all these venomous animals and come up with what is the most lethal animal to humans.
02:57Not too sure what that'll be yet, but I think we're actually going to find a few surprises along the
03:00way.
03:02Let's take a look at the weapon itself.
03:06While most of us will have heard of venom, how many actually know what it is?
03:13Venom is a mixture of biological toxins.
03:16Unlike a poison which must be swallowed or absorbed through the skin,
03:20venom is injected into the body during a sting or a bite.
03:27It can be used for hunting by disabling prey or as a defensive weapon in the face of attack.
03:35The difference in strength and how the venom functions will have a significant effect on how it works on the
03:41human body.
03:43Something that Jamie Seymour has learned firsthand.
03:49His new study will take him up against the creature that most people think of when they hear the word
03:54venom.
03:55The snake.
03:58There are more than 30 species of rattlesnake alone, all carrying different venoms.
04:05While some venoms target the body's nervous system, creating havoc with the complex network of nerves that control its vital
04:12functions,
04:13others attack flesh and tissue, effectively starting the digestive process before the victim is even eaten.
04:22Having bitten its prey, the rattlesnake waits for the venom to take effect before feeding.
04:37Someone who has handled plenty of these creatures over the years is Jules Sylvester.
04:42Good place.
04:43He's been helping movie makers to get their dangerous animal footage for many years.
04:48And he's taking Jamie to find North America's most dangerous rattlesnakes and get a venom sample for future testing.
04:55But in this rugged terrain, this medium-sized rattler is extremely difficult to spot if you don't know what to
05:02look for.
05:02You can be standing right on top of a metre-long Mojave and still not see it.
05:08So Jamie Seymour has taken the precaution of wearing bite-proof Kevlar leg protectors.
05:22Oh, Jules, Jules.
05:25That's a Mojave.
05:26Very, very potent neurotoxin.
05:28It's most unusual because most rattlesnakes are hemotoxin.
05:31That's neurotoxin.
05:32The Mojave's venom is a complex cocktail of enzymes and other proteins, forming an incredibly strong neurotoxin.
05:39Designed to block the firing of nerves, particularly those controlling the muscles.
05:44It's the quickest way to stop prey in its tracks.
05:49Nothing like the amount of venom we're getting from the other one.
05:51Knock nerves out, and it's game over.
05:54It's paralysis, even death.
05:57That's amazing, isn't it?
05:58The Mojave rattlesnake is not the only rattler in these parts.
06:01In the lower desert nearby is the larger and more infamous Western Diamondback.
06:09But despite their overlapping territories, each has a very different venom.
06:16Got you. Yeah, I got him. I got him.
06:19The Western Diamondback carries hemotoxic venom that attacks blood vessels.
06:24Like many snake venoms, it starts the chemical breakdown of flesh even before the victim is eaten.
06:31And that is your classic Western Diamondback rattlesnake.
06:36All the cowboy movies, this is the best Hollywood snake in the world.
06:39These guys account for more snake bites than any other snake in the country.
06:43It's obvious the rattles make a noise, and then what do you want it for?
06:46It's a warning for probably bison not to step on him.
06:50It's a go away, leave me alone.
06:52The Western Diamondback is more widespread and likely to be found at the edge of towns and cities.
07:07Another American rattler has adapted to a rather different habitat.
07:11The Southern Pacific rattlesnake prefers the green coastal climate of the Hollywood Hills.
07:17The Southern Pacific rattlesnake is the only one that's venomous in the LA area.
07:20Even though we've got thick bush here, we're one hour from Hollywood.
07:24Previously categorized as a B grade or low risk, this species is now emerging as a major threat to people
07:30living in the Los Angeles Basin.
07:34As specialist snake bite physician Dr. Sean Bush knows only too well.
07:39Mostly we see Southern Pacific rattlesnake bites because those snakes live where the people like to live.
07:45That is along the coastline and up in the mountains.
07:48These snakes often stray into people's driveways and backyards, and though it may be tempting to try and remove them,
07:54it is always best to exercise caution and call for help, as this man discovered the hard way.
08:00I took things into my own hands and made a big mistake.
08:06And within an hour or two, my hand was blown up like a balloon.
08:11This hospital is used to treating several snake bites a day.
08:15And when Dr. Bush received a phone call to let him know his own child had been bitten, he feared
08:21the worst.
08:27My son was actually in the backyard and picked up a little rattlesnake and got bit.
08:33We actually had five snake bite patients in the hospital that day.
08:36My wife pages me 9-1-1. You know, I'm thinking the worst.
08:41And I've seen all kinds of bad things happen to people with snake bites.
08:51Fortunately, he did well. His hand is just a little bruised right now.
08:55He has a little trepidation around snakes now, which maybe he should.
08:59Are you going to touch it?
09:00I'm not going to touch it again.
09:04Bye-bye snake.
09:05Goodbye snake.
09:11With its tell-tale menacing sound, the rattlesnake is in fact one of the easiest venomous snakes to avoid.
09:20The rattle is a benign early warning system.
09:23A device for making sure that anything that comes near is made aware of its presence.
09:32The way? Come on, big boy. Look at that. Isn't that nice?
09:37A venomous snake stores its venom in glands just behind the eye,
09:41where it can rapidly supply venom to the injection mechanism,
09:45either hypodermic-like fangs or finely grooved teeth.
09:52The fangs of rattlesnakes are hinged, rotating down into a stabbing position just before a strike.
10:01So how do the rattlesnakes we've seen so far score against Dr. Seymour's ranking system?
10:07One is particularly dangerous to man.
10:12It's the notorious Western Diamondback.
10:17Because this rattler is now commonly seen around southern US towns,
10:21it has more opportunity to strike at people,
10:24which, given its bold, aggressive nature, it frequently does.
10:29Its large hinged fangs penetrate deeply into its victim to deliver its venom.
10:36And though not as potent as that of other rattlers,
10:38it can deliver enough venom to be potentially fatal if a bite goes untreated.
10:45The Western Diamondback is responsible for the most bites and deaths by any reptile in the United States.
10:56Next, we head 12,000 kilometers away to Africa, where we discover a snake whose fangs dwarf those of any
11:03rattlesnake.
11:05Much of Africa's Western Central regions are still covered by thick forest.
11:10It's here, along the forest's edges, that we find a snake with a particularly dreadful reputation.
11:17When it comes to death by lethal injection, the Gaboon Viper really can deliver.
11:23This solid-bodied, one-and-a-half-meter but slow-moving snake is a superbly camouflaged ambush predator.
11:31It's so well disguised that it's nearly impossible to see it, even when you know it's there.
11:38Through its five-and-a-half-centimeter fangs, the longest of any snake,
11:42it injects the largest quantity of venom in the snake world.
11:50This is thankfully not an aggressive species, preferring to retreat rather than attack if approached.
12:02For any snake, envenomation of a human being is a waste of time and energy.
12:12A snake who's injected valuable venom into a human victim may have less chance of hunting prey
12:18or defending itself from attack until it has replenished its toxic supplies.
12:25And there are plenty of animals that will attack even the most venomous species of snake,
12:30like the mongoose.
12:35And in Mozambique, they face a snake that can deliver its venom long distance.
12:44The spitting cobra takes the defensive use of venom into a whole new league,
12:51squirting venom with astonishing accuracy.
12:58Muscular contractions squeeze venom through the fangs,
13:01spraying it up to three metres at the eyes of any aggressor, causing irritation and blurry vision.
13:09But there's another African snake more deadly than the cobra,
13:13the highly confrontational, sore-scaled viper.
13:17With its subtle signature sound, it inhabits a vast natural range,
13:22which stretches from North Africa across the Middle East and into Asia,
13:26to include areas of mass human population, well over a billion people in all.
13:34Giving this aggressive serpent plenty of opportunity to bite.
13:41Professor Julian White is a medical expert in diagnosing snake bites.
13:45Ten percent, approximately, of acute hospital beds in Nigeria are occupied by snake bite patients,
13:51and the overwhelming proportion of those are sore-scale viper bites.
13:57Its huge range, and the fact that victims are often a long way from proper medical treatment,
14:03ensure this is a serious bite-risk species.
14:09So, while the gaboon viper has the most formidable set of fangs and is physically the more intimidating,
14:15it is actually the smaller, sore-scaled viper that is the greatest threat to people living in its territory.
14:23This deadly predator gets plenty of opportunity to strike.
14:27And, unfortunately, it is also extremely bad-tempered, and is often known to attack humans.
14:35Despite its small size, it has an impressive set of folding fangs,
14:39which can inject a fatal dose of moderately toxic venom.
14:43All in all, it kills thousands of people every year.
14:49Seven thousand kilometers away in Asia, we find several other contenders for the world's worst venom.
14:54While most people try to avoid close contact with venomous snakes,
14:59here there are some who caught danger on a daily basis.
15:06Sacred among Buddhists and Hindus, the Asiatic Cobra is a confident species and will bite if alarmed.
15:14The Asiatic Cobra is also a bit of a show-off,
15:17and its threat posture has become an iconic symbol of Asia.
15:25Coming face to face with these snakes,
15:27Thai snake charmers uphold a tradition that goes back thousands of years.
15:33If any snake had an opportunity to bite handed to it on a plate, it would be this one.
15:40But the Asiatic Cobra is dwarfed by a gigantic relative,
15:44the longest of all venomous snakes, the King Cobra.
15:49At over five meters in length, the King Cobra can raise enough of its body from the ground to stare
15:55a standing human in the face.
16:01Many of the charmers who work with King Cobras believe they have a high level of intelligence,
16:06and it's possible the reptilian performers only deliver dry warning bites, injecting minimal venom.
16:14In the wild, they mostly save their huge venom capacity for their favourite prey, other snakes.
16:23However, this part of Asia does have a problem with another more irritable snake, the Russell's Viper.
16:33Russell's Viper is especially nasty throughout its range.
16:37It not only causes kidney damage, nasty bleeding effects,
16:41and in some places, particularly for instance Sri Lanka, can cause degrees of paralysis and muscle damage as well.
16:49This snake is one of the most dangerous in all of Asia.
16:53Preferring the outskirts of cities, it kills thousands every year.
17:00Many of this snake's victims are farmers whose remote rural location
17:04prevents them from getting the immediate medical attention this bite requires.
17:11It can take days before a victim can reach hospital, long enough for the venom to do serious damage.
17:18The Russell's Viper strikes at close range, and a single bite can deliver over 100 milligrams of venom.
17:28As the venom diffuses into the bloodstream, it interrupts the blood clotting mechanism,
17:34leading to hemorrhaging and finally to devastating kidney damage.
17:41Let's consider the worst-case scenario.
17:43What do you do if you're bitten by a venomous snake?
17:47Forget sucking out the venom. That's strictly for the movies.
17:52Wherever you are in the world, a serious venomous snake bite without proper medical attention
17:57can lead to permanent injury or even death.
18:05In most cases, you need an injection of antivenom.
18:08This is an antidote created by injecting small amounts of the true venom into a host animal such as a
18:14horse.
18:17The immune response which follows produces antibodies against the venom.
18:22These are harvested from the animal's blood to make antivenom.
18:26We use predominantly horses because, one, they're big and you can get large volumes of blood from them
18:32without causing any problems to the horses.
18:33The second thing is there isn't a great deal of diseases that can be passed on from horses to humans.
18:39What basically happens is you take the venom, you inject it into a large horse,
18:44you give it a small amount, and over time you increase the amount of venom that you give to it.
18:48What the horse does is its immune system then starts to produce antibodies.
18:53What do you think is chewing gum as being this antibody that I'm producing?
18:56I'm the horse.
18:59You have this antibody now and what happens is the venom is a particular shape because it's going to act
19:05and lock in almost like a key into a door.
19:07Now if I can take this antibody and wrap that up, that key will no longer work.
19:12So it will float free in the body but it won't be able to lock onto the bits and pieces
19:17in the cells
19:17and cause death and problems for humans.
19:20While antivenoms will neutralise the toxin, they cannot reverse the process of any damage that's already done.
19:25Being monitored in hospital is often essential.
19:34But there's one snake bite where even without antivenom it is possible to survive.
19:40The Malayan crate is one of the few Asian snakes carrying a purely neurotoxic venom.
19:47As a nocturnal hunter, it stalks its prey in darkness by following scent trails, often entering through an open window
19:54or door.
19:59And the sleeping inhabitants may never even know they've been bitten, especially since the fangs are very small.
20:10As the neurotoxin goes to work, it's only the unnerving paralysis on waking that points to a snake bite in
20:16the night.
20:17The toxin blocks nerve endings that control muscles, including the rib muscles vital for breathing.
20:27But unusually, this venom can work its course through the body and as long as the victim can be kept
20:32breathing through the paralyzing effects, they are likely to survive.
20:39While both Russell's viper and Malaysian crate present a serious threat to southern Asia's human population, it's the cobra that
20:46is the greatest danger here.
20:49Not the mighty king cobra, the largest venomous snake in the world, but its smaller cousin, the common cobra.
20:55And again, we turn to Jamie Seymour's new classification system.
21:02The Asiatic cobra is most commonly found on the Indian subcontinent, but its habitat extends further into southern Asia and
21:10it shares its living space with millions of people.
21:15Its confidence also contributes to it biting up to 15,000 people every year.
21:22While its fangs are not the biggest, the snake does produce a surprisingly large volume of venom.
21:31Thankfully, its venom only scores moderately on our potency scale.
21:35Nevertheless, it remains one of the biggest killers in the venomous world.
21:45But there is one country that tops all the others put together in the venomous snake stakes.
21:53Australia. Its species of venomous snake outnumber the non-venomous ones.
21:59Australia is a big place with vast areas of unpopulated country.
22:03The snakes that live here are hardly pushed for space.
22:08Yet alarmingly, there are seriously venomous species that have adapted perfectly to the urban lifestyle of Australia's cities.
22:17Some eastern brown snake populations now thrive on a diet almost entirely consisting of house mice.
22:26A great pest control perhaps, but being caught by the jaws of this mousetrap is surely worse than having a
22:32bad rodent problem.
22:34And they inject a good deal more venom than was previously thought, and like a lot of city dwellers, they
22:39are easily annoyed.
22:43The venom of the eastern brown is particularly unusual because it causes the blood to clot rapidly.
22:49However, if you survive, you may later die from hemorrhaging.
22:54But only by travelling to the remote regions of the Australian outback can we find the even more venomous and
23:00ominously named fierce snake.
23:04If that snake, with that sort of venom, was present in a highly populated area, I suspect you'd be dragging
23:10people out of the bush left, right and centre as they die.
23:12The fierce snake is also known as the inland taipan.
23:16It inhabits a harsh and extremely demanding environment.
23:24They specialise in hunting native desert mammals, and tracking prey down takes valuable energy, so failure is not an option.
23:34When the prey turns up, you want to make sure you grab it, you want to make sure you inject
23:38it, and you want to make sure it's going to die.
23:40So you give it a very potent venom and you give it a heap of it.
23:44But fierce by name doesn't necessarily mean fierce by nature.
23:48This snake, with the most lethal venom known for any land animal, is hardly ever seen by a human being.
23:59It hunts and lives in holes and subterranean tunnels, rarely venturing into the open.
24:07But very similar toxins to those found in the fierce snake can also be found in a snake much closer
24:13to home.
24:19Around Australia's coastlines, we find a highly venomous sea serpent.
24:24The olive sea snake is gregarious and confident around human beings, and can frequently approach divers and snorkelers.
24:36They need a powerful, fast-acting venom.
24:39If they don't disable the fish quickly, it will escape, and the meal is lost.
24:48But of all Australia's snakes, it's not the sea snake that comes out top, nor is it the serpent with
24:54the strongest of all venoms, the fierce snake.
24:58In Australia, it's the eastern brown snake, which ranks as the most dangerous to people.
25:05It is aggressive and fast-moving.
25:12Fortunately, its fangs are relatively small, and it rarely manages to cut through heavy clothing.
25:22Historically, eastern browns were thought to produce a tiny amount of venom, but recent studies suggest that this is not
25:28the case.
25:32And their venom has a rare blood clotting quality, which, if delivered directly into the bloodstream, can kill a human
25:38in minutes.
25:48Australia does have more than its fair share of venomous creatures, and they're not all snakes.
25:55There are hundreds of other species that can sting and bite.
26:06This is the Sydney funnel-web spider.
26:12As its name suggests, it lives in and around the city where it's known to have killed at least 13
26:17people.
26:18These are the only spiders in the world which are truly lethal.
26:23Prior to the development of anti-venom, there was nothing that medicine could do to guarantee survival, even in an
26:29adult, from a major funnel-web spider bite.
26:32Both male and female spiders carry venom used for killing their insect prey,
26:36but it's the male's extra venom component that's a danger to people.
26:41The females seldom leave their underground burrows, whereas males often wander in search of females.
26:50Staying hidden helps to avoid predators, but for the times when it does venture out into the open, the spider
26:56has developed a highly potent toxin, which it can use if threatened.
27:02There's another venomous Australian spider that resides far beyond the city limits, the redback, and it's notorious for lurking in
27:11dark, dry places, often right under your nose.
27:15In Australia, more anti-venom is used to treat redback spider bite than all other bites combined, including snake bite.
27:23It's a very common problem, with probably greater than a thousand cases receiving anti-venom every year.
27:29And this species is also well-travelled, they've a fondness for long-haul luggage, and they've found themselves 7,000
27:36kilometres away in the port of Osaka, Japan.
27:41It arrived on the Osaka docks probably around 1994, and quickly spread, so that by 1996 there were probably maybe
27:49hundreds of thousands of redback spiders in Osaka.
27:52I found higher concentrations around the dock area than you normally see even in Australia.
28:00Back in his North Australian lab, Jamie Seymour takes a closer look at these spider venoms.
28:08And it is the Sydney funnel-web that poses the greatest threat to humans, according to the five-point scale.
28:19During the mating season, funnel-web males are drawn into gardens and houses, increasing the likelihood of a human encounter.
28:28And though it might rather avoid confrontation, it will not shy away from defending itself.
28:35Despite feeding mainly on insects, its fangs are long enough to pierce human skin and deliver a small quantity of
28:43highly potent venom.
28:52Back on our quest to find the world's worst venoms, Dr. Jamie Seymour and venom enthusiast Jules Sylvester head back
29:00to the desert in search of the only lethal species of scorpion in the United States, the Arizona bark scorpion.
29:09While spiders and snakes deliver their venom through fangs to inject it into the bloodstream, the scorpion uses its sting
29:16in the tail.
29:19After snake bite, scorpion sting is probably the medically most significant cause of envenoming in the world.
29:26We have no idea how many people are affected, but I would suggest it's probably into the millions.
29:32Jamie Seymour is back with Jules Sylvester, this time carrying an ultraviolet light to bring out the natural fluorescence of
29:39the scorpion's hard external skeleton.
29:42This is the big one, but not the bad one.
29:45Try under that piece of bark at the top there.
29:51That's a bark scorpion.
29:52You got one?
29:54Grab him, grab him.
29:56You get one?
29:56Yep, absolutely.
29:57Here you got a bark scorpion.
29:59Look at that.
30:00Doctor, just ten years ago, they were losing about 800 people in Mexico just because of this.
30:05Seriously, with the advent of the anti-banane, that's fixed that.
30:08Improved it a lot.
30:14Found in the American Southwest and Northern Mexico, the bark scorpion does encounter human beings fairly often, but is unlikely
30:22to sting unless provoked.
30:28Being small in stature, it has a relatively modest stinger delivering small quantities of venom.
30:34But compensating for its lack of size, its venom is relatively potent, and prior to the development of proper anti
30:41-venoms, it was a much feared killer.
30:46It's back in Africa that we find two other particularly notorious scorpions.
30:55This is the powerfully built fat-tailed scorpion.
30:58It grows up to ten centimeters in length.
31:03Though its sting is designed to immobilize insects, it can have an equally potent effect on a child, although this
31:10species rarely ever injects enough venom to kill a healthy adult.
31:18The distinguishing feature of most scorpion stings is that the toxins they contain have a very different effect on the
31:24nervous system than any of the snakes we've seen, sending it into a kind of physiological overdrive, with heart rate
31:31and blood pressure since soaring.
31:38Another African scorpion is a wolf in sheep's clothing.
31:43The Deathstalker more than compensates for its small size and unimpressive looking stinger by having more toxic venom drop for
31:51drop than any other species of scorpion.
32:03Jamie Seymour's scale highlights why it is so deadly.
32:08Opportunity to strike is high.
32:10It's the cause of many stings throughout the Middle East and North Africa where it lurks.
32:18For aggression, it also ranks highly.
32:21They can be very volatile.
32:25It has a highly effective stinger that easily penetrates human skin.
32:34Scorpions restrict the tiny amounts of precious venom they administer with every sting.
32:39Which is fortunate because the Deathstalker has extremely potent venom which can cause heart and respiratory failure if injected into
32:48a person's bloodstream.
32:54For our final group of venomous creatures, we return to Australia, but this time we're underwater.
33:03Everything Jamie Seymour needs for this category is right on his own doorstep.
33:08Australian waters contain many species of dangerous marine stingers and biters, but sometimes it's not the venom which delivers the
33:15lethal blow.
33:17And he was present on a particularly fateful day.
33:21When Steve Irwin was stung with a stingray, I was on board and had been for a couple of days
33:26with Steve.
33:26And what appears to have happened is Steve swum over the back of the stingray.
33:30From the animal's point of view, there's a big shape coming over the top of it.
33:34A big shape in the water normally means big predator.
33:43It was not the stingray's venom that actually killed Irwin, it was the puncture wound from the ray's spine.
33:52It's not unusual to see, certainly in tiger sharks and other big sharks, these holes or these gaping wounds around
33:59sort of the middle of the shark or down through the gills.
34:03Think of this as really a sharp knife. So if that's embedded through your chest and ends up unfortunately somewhere
34:09like your heart,
34:10it's not the venom that does the damage from humans, it's more the physical damage from these big spines.
34:17There are other marine creatures here that are lethal to human beings.
34:22This is the blue ringed octopus.
34:25And this is Dr. Mark Norman. He's an octopus expert at Museum Victoria.
34:31These octopuses are equipped with a really good warning system and it's using brilliant blue rings to flash like police
34:39lights to say I am really deadly and if you come too close I'll bite you.
34:46The venom it carries consists of a highly specialised protein called a tetrodotoxin.
34:51It has evolved to paralysed prey like crabs quickly.
34:56The venom is supplied to the razor sharp parrot like beak from large venom glands deep inside the octopuses body
35:03immobilising its prey.
35:05And they have an equally disastrous effect on the human body.
35:09In situations where people have died from the bites of these octopuses, they've been handling them and they've bitten with
35:16this very powerful saliva going into their bloodstream and within three minutes they're paralysed and they suffocate to death.
35:24Worse still on the list of Australia's most deadly venomous creatures is the harmless looking box jellyfish.
35:40Each tentacle is armed with millions of minute spring-loaded stinging capsules.
35:46They inject venom into blood vessels just beneath the skin where it travels rapidly through the bloodstream and eventually to
35:53the heart.
35:59And unfortunately it inhabits inshore waters, the kind frequented by swimmers.
36:09Jamie Seymour has been on the wrong end of the box jelly's tentacles more than once.
36:18And I've got to tell you, I mean, it hurts. It's almost a surreal pain, but it reaches its peak
36:23level almost instantaneously and stays at that level for about 10 to 15, maybe 20 minutes and then it just
36:29shuts off.
36:30To protect swimmers from the box jellyfish, special nets at the most popular beaches keep them well apart.
36:38You see these stinger nets all over the place and they do a wonderful job. We've never had a fatality
36:43or a near fatality sting inside the nets.
36:46You swim outside the net, it's not a matter of if you get stung, it's when you get stung and
36:51it's really playing with your life.
36:53But the nets, which do a good job of keeping the deadly box jellyfish out, are no barrier against another
36:59member of the jellyfish family, one of the smallest killers in the ocean.
37:03Along coastlines and reefs from Australia to Southeast Asia is the miniscule Irukandji jellyfish.
37:11We started getting jellyfish from inside nets. They weren't big box jellyfish stings. They were distinctly different. They were showing
37:19distinctly different symptoms.
37:21Often no larger than a pea, no normal stinger mesh can keep out the tiny Irukandji jellyfish.
37:32As I've duck died down, I've got stung across the top of the lip.
37:38But unlike the box jellyfish, the venom of the Irukandji lingers in the victim's tissues.
37:46It's this that gives the sting a delayed reaction.
37:50Seymour suspects that it's only when the toxins reach the body's lymph glands that the painful effects kick in.
37:57I had severe stomach cramps.
38:00Hins and needles through the lower joints and the legs like you would not believe.
38:05And we're now getting large quantities of painkillers and it was just hell on earth.
38:14Far less dangerous to people but fatal to fish is another bizarre marine killer, the cone shell.
38:25Whereas most venom's lethal impacts are based on just a few key proteins, that of the cone snail contains hundreds
38:32of toxic compounds.
38:34Among them are nerve blocking chemicals that can induce instantaneous caesia and a strong sedative that prevents the prey from
38:41struggling.
38:42But like most snails, this one operates at a pretty sedate pace.
38:46It only needs to feed once a week and its super strong venom guarantees that when it does hunt down
38:52prey, it almost always makes a kill.
38:56However, scientists have actually discovered a way to utilise this venom as a super strong painkiller.
39:02Now these animals are cone snails. I mean, they're basically little chemists.
39:06There's already been a painkiller that's been extracted from the venom and who knows what else may be in there.
39:16Scientists are now beginning to explore the possibilities of using its natural properties to treat serious diseases of the human
39:22body.
39:24As research continues into the medicinal potential of venom, in the natural world it's still a formidable weapon.
39:31And in the ocean, the deadliest of all venomous creatures is the box jellyfish.
39:37It inhabits waters surrounding many popular beaches where stinger nets are deployed to keep bathers safe.
39:45It is not an aggressive creature and won't deliberately attack a human being, but nor is it likely to get
39:51out of the way.
39:56When fully grown, it has over 120 meters of tentacles, armed with millions of tiny stinging capsules, making it highly
40:04effective at injecting its venom.
40:08The amount delivered depends on how severe the contact with its highly armed tentacles.
40:17And it gets worse. The venom it delivers may well be the fastest acting and drop for drop one of
40:23the deadliest known against people.
40:25In severe cases, death can occur in just two minutes, before any chance of medical help.
40:33Of all the creatures we've seen in action, from the rattlesnakes of the United States and the venomous spiders of
40:38Eastern Australia, to octopus and jellyfish,
40:41which one is responsible for the greatest number of human fatalities?
40:48According to Dr. Seymour's ranking system, we can focus on three final contenders for the title.
40:55From the reptile world, it's the feisty, sore-scaled viper, which narrowly edges out the common Asian cobra and Russell's
41:02viper, to be the world's most dangerous serpent.
41:07Among the spiders and scorpions, it's the death stalker that tops the lethal list.
41:12And from the marine contenders, it's the ghostly box jellyfish.
41:24Surprisingly, many creatures with extremely toxic venoms measured drop for drop don't feature amongst our finalists,
41:31simply because they don't get the chance to encounter humans often enough to rate among those most dangerous to people.
41:47But there is one merchant of venom that narrowly defeats all the others in the danger it poses.
41:59According to our key criteria, the most dangerous venomous creature on Earth lacks a big Hollywood reputation.
42:05In fact, few of us will have heard of it until now.
42:09The sore-scaled viper.
42:12You find it through North Africa, Asia and the Middle East.
42:16And through that area, there's something like a billion people inhabit that area.
42:20And probably 60, 70, 80, 100,000 people a year get bitten.
42:25Out of that, 20,000 people die each year.
42:29Its lethal credentials include a highly potent venom.
42:33But what really sends the fatality rate soaring sky-high is a unique combination of this snake's aggression and proximity
42:41to people,
42:41making rapid and efficient medical treatment crucial for survival.
42:46Now, it's not because this animal has such a lethal venom that people are bitten and die instantaneously.
42:52It's predominantly because they can't get to medical help quickly enough or they don't have good antivenin.
43:00Reducing the human death rate from venomous bites and stings means making sure that more people in bite risk zones
43:06can get fast and effective treatment.
43:12And there is another crucial factor in determining the toxicity of any venom.
43:17Among the creatures we've already seen, there are extremely variable reactions to their bites and stings.
43:30jekes
43:31Take the Sydney funnel-web, potentially deadly to humans.
43:34Its venom has almost no effect on the local cat and dog population.
43:40This venom appears to be especially toxic to monkeys and humans, but harmless to felines
43:46and canines.
43:49However, when it comes to the bite of the North Queensland tarantula, it's the other
43:53way around.
43:54Human beings suffer localised pain, while cats and dogs usually die.
44:00And surprisingly, it is a specific reaction to venom that makes one species an unlikely
44:06mass killer, the humble honeybee.
44:11While many of us would shudder at the prospect of venomous snakes and scorpions in our backyard,
44:16it's actually bee stings that kill more people in the Western world than any other species.
44:21It's not direct effects of the venom, but it's because people go through what they refer
44:25to as anaphylactic shocks.
44:27In other words, they're allergic to these bee venoms.
44:30Things happen like the muscles around your neck swell up and you stop breathing.
44:33And that's what kills.
44:38Such a significant difference in reaction to venoms has also inspired Jamie Seymour to plan
44:43another element for his venom rating system.
44:48Lab-based experiments designed to find out exactly how severely each of the world's most
44:54toxic venoms actually attacks human cells.
44:57The reason for this is simple.
45:00What they've done routinely is test them on mice or rats, which works well if you want
45:05to know how lethal these are against rats and mice, but it doesn't tell you anything about
45:09how lethal they are on human cells.
45:12So far, Dr Seymour has begun experiments on human heart cells.
45:16Not people of course, but cell cultures specially grown for the purpose.
45:21So these containers here are the key to everything we're doing.
45:24Basically what we've been able to do is grow human cells.
45:27We have about 10,000 cells in each little well.
45:31We can add venom from any sort of animal we want.
45:34Having done that, we can then add a dye to it.
45:37And that dye will stain up red as the cells die.
45:40So more and more cells die, the redder the material in there becomes.
45:44The results are already proving invaluable.
45:48Venom from the controversial Sydney funnel web spider has been confirmed highly toxic,
45:53exceeding the drop-for-drop potency of the deadliest scorpions tested.
45:58Among the reptiles, the most toxic venom tested belong to the inland taipan,
46:03killing over 60% of heart cells in the first 10 minutes.
46:07Thankfully this snake remains remote from human contact in the Australian outback.
46:12But the most astounding result is the extraordinary toxicity of the box jellyfish venom,
46:18which began killing human heart cells virtually on contact
46:21and which destroyed 100% of all cells within 10 minutes.
46:26Jamie Seymour has long suspected that box jelly venom is both extremely potent
46:30and fast acting on humans as well as fish.
46:33Now he has the first clinical proof.
46:38While his groundbreaking research into the effects of venom on human cells is just beginning,
46:43there are scientists already exploring venom's potential to cure arthritis, heart disease and cancer.
46:50So these toxins may not always be bad news for human beings.
46:55Who knows, we may one day owe our lives to some of the most dangerous venomous creatures in the world.
47:04So these toxins are webpagey,
47:07we're not able to eat cause death to many people,
47:08they're not about to bit to infect.
47:13The next thing shows us all about this.
47:13Oh, I can't wait for you!
47:17This is the only way to become a victim,