Deadliest sea creatures venom survival and life saving medicines

When hunting, most undersea predators rely on razor-sharp teeth, lightning speed or brute force. But there are also creatures that feed and defend themselves with more subtle but no less effective weapons. For many animals, survival depends on a powerful discharge of venom. The poisons of certain marine species are among the most lethal found in nature. The sting of a box jellyfish or stonefish can inflict excruciating pain and even kill a human. In an ironic twist, these potent toxins are now sources of new wonder drugs. Deadly cone snails have helped researchers discover innovative ways to treat severe pain and a host of other human ailments. For these seemingly defenseless animals, life hinges on their lethal arsenals of venom. In a coral garden, animals of every shape and description weave a living tapestry. This is the enchanting realm of the tropical reef. In this undersea city, the struggle to survive is the driving force behind the lives of all creatures. Many animals are both predators and prey, and one of the most effective tools for survival is venom. Some species use conspicuous, even flamboyant displays to advertise their toxins, while others rely on more subtle means to eat or not to be eaten. Of the many creatures which utilize venom, only a handful are deadly to humans. Of all undersea animals, sea snakes have one of the most potent toxins. Their venoms are far more powerful than those of most terrestrial snakes. Just a few drops are enough to kill a human. Many divers and swimmers have had the unnerving experience of a curious sea snake approaching or even touching them. For humans, there's really very little danger unless the snake feels threatened. They're a wonderful animal to work with under the water because they're not threatened by us, and so we can handle them. As long as you're gentle and they don't feel stressed, then they're really a very easy animal to work with. Dr. Glenn Burns is one of the world's foremost sea snake specialists. Over the past two decades, he has captured and studied hundreds of the animals. His research has helped to dispel many of the myths surrounding these intriguing creatures. The danger to humans from sea snakes has been greatly exaggerated. They are far less likely to bite us than virtually any venomous snake. Like other deadly species, they can be safely handled. The inquisitive reptiles look at divers as just another piece of reef to explore in a search for their favorite foods. We are clearly a greater threat to them than they are to us. Alright, let's take her out of the bag, measure him, and we'll check him for a tag. This one's actually a male. The males actually don't grow as big as the females, but this is a big male. So what we might do is we'll pop him up here on the bench, and if I hold the body in, I'll get you to handle the rest of the body, and we'll measure him, and we'll get a length on him. Because sea snakes have little fear of man and are relatively easy to capture, they are often killed for their meat and skins. Motorboats and fishing trawlers also take a heavy toll. Trapped in nets, the air-breathing snakes easily drown. In a number of areas of the Indo-Pacific, sea snake numbers are declining dramatically. You can read it off of the vent there. Oh, she's cranky. I want to get a snout vent measurement, so if I hold the tape here, can you just read it off on the vent? Yeah, it's a 1.25 snout vent. She's wriggling. Okay, so that's a 1.25 snout vent. Beautiful. Now, see, when she starts to twist like this, it's better to put her down because I don't want to damage her. Okay, lay her body down, and let her go. People who are usually bitten by snakes are handling them, either on deck, the way we have been, or fishermen, trying to get them out of nets, for example. When someone is bitten by a sea snake, the rapid use of antivenom is crucial in helping the victim survive potentially fatal symptoms. Burns milks the snakes of their poison, which is then sent back to serum labs to be developed into antivenoms. Okay, let's see what she wants to do. Okay, so she gave most of her venom then, just in one bite. You can see it there in the bottom of the glass, and that's a lethal dose. That's enough to kill us both. If she bit me now, she's still potentially capable of delivering a lethal dose of venom, even though we've just milked her. When she bites you, you don't really know how much venom that she's pumped into you. It may be a dry bite. I was bitten once before, and it was a dry bite. I was bitten, but not envenomated. And you don't know. You don't know whether you have any venom in you until you start to show symptoms. Okay, so if you can take her head, I'll just... You alright there? Beautiful. To distinguish individual snakes, Burns utilizes an electronic microchip called a PIT tag. With a minor surgical procedure, he inserts the tiny device directly into the animal's body. There it goes there. With a database of hundreds of snakes, Burns can track their migrations along the Australian coast and help identify animals killed in fishing nets or by boats. With much of sea snake behavior and biology a mystery, there still remains a lot to learn about the enigmatic reptiles. One of the reasons that we know so little about sea snakes is the fact that they are so venomous. People tend to shy away from a potentially dangerous animal like that. It doesn't really lend itself to close observation. I've been working with sea snakes for 20 years now, and I'll continue to work with sea snakes. I still find them fascinating. There's so much we don't know about them. I mean, so far we've been able to track some individuals, but we've only been able to do it with one species, and there are so many more species to work with. So, you know, I'll continue to work with sea snakes, absolutely. It's a very cranky snake. The venom of this marine animal is also one of the strongest toxins on Earth. But its deadly poison is also giving new hope to patients suffering from acute pain. Australia's Great Barrier Reef. Stretching for over 1,200 miles along the country's eastern coast, the reef is the largest community of living organisms on Earth. To study one of the ocean's most poisonous animals, researchers from the University of Queensland travel from the port city of Gladstone to remote Heron Island. Located at the extreme southern tip of the Great Barrier Reef, Heron Island is a renowned bird sanctuary. It's also a staging point and research center for scientists from around the globe. This particular mission, to collect deadly cone snails and extract their lethal toxins. Per milligram basis, the venom of this tiny marine mollusk is one of the strongest poisons found in nature. Good for their beautiful shells, many collectors, divers and beach walkers have discovered that the attractive snails pack a powerful punch. They've been the cause of hundreds of serious injuries and several documented deaths. Their venom is strong enough to paralyze or kill a human. In the envenomation process, most individuals feel a sharp pain. They have a feeling of loss of control of body function. Their blood pressure can either go up or down. They have trouble moving, trouble breathing. The neurotoxins of certain cone snails are so powerful that they can cause the human respiratory system to shut down. While fully conscious and aware, many victims lose the ability to breathe or the heart simply stops beating. Dr. Paul Alewood is a professor at the University of Queensland and a founding member of the Xenome Project. Xenome is a pioneering leader in the research and development of new medicines derived from the venom of toxic animals. And the venom of the cone snail is likely the world's richest treasure trove of new drugs. With over 50,000 different toxic proteins, or peptides, the cone snail family promises the most important pharmacology of any animal species. With the right dosage and combination of peptide molecules, these poisons appear to be highly effective in the treatment of a number of human ailments. Each countertoxin impacts upon a different nerve system in humans. Some of these relate to pain, others to blood pressure, others to mood, and others to muscle control. So they're a huge source of potential drugs. Australia is home to 100 of the world's nearly 600 species of cone snails. Heron Island, with its immense surrounding reef, is an ideal collection site. We'll go out, straight out there. I think it's going to be another half an hour. Yeah, I think so. It'll be half an hour to get out to there, in any case. Okay, well the tide's still a fair way to go. Going to head out there? Let's stop and have a look where we're going. Where's that pointer? The marker. During extremely low tides, Aylewood and his colleagues fan out across the shallow reef to search for cone snails. Let's do it. Oh, beautiful. Nice one, guys, over here. Capitanus lives on top of the rocks, and you can see by the growths on the shell. Whereas underneath, it's all nice and shiny. No, nothing there. Good find. Pretty. Got something? Oh, yeah. Oh, very nice. Yes. Beautiful, beautiful. Lovely and shiny. Living under the rock? Mm-hmm. Straight under that... Kind of striatus? Mm-hmm. The researchers need only gather one or two snails of any given species. Their toxins can then be analyzed, sequenced, and replicated in a lab. The collection of a small number of animals has a negligible impact on mollusk populations. It's a Bernius or a Braius. Good. Yeah, absolutely. It's just a young snapper. There's nothing there. Certainly the unglamorous bit of tan hunting. After dark, the animals are more active as they leave their coral hideaways to feed. At 2 a.m., the crew returns to the reef to search for the nocturnal hunters. Well, with a bit of luck, they're cruising around in the evening. In principle, they should all be awake and out. In practice, it's pretty hard to see them in any case. Cone snails prey on worms, other mollusks, and fish. And it's the species that hunt fish that are most deadly to humans. As we are also vertebrates, like fish, these toxins unfortunately target our physiology. The mollusks can smell their quarry from a considerable distance. Their mantle is drawn out and forms a siphon through which water enters, providing respiration. But also alerting them to the presence of their prey. At night, most fish are asleep. Closing in on a goby, the slow-moving snail readies its deadly harpoon. In seconds, the fish is immobilized and the mollusk wastes no time in ingesting the huge meal. The meal will satisfy the snail's hunger for several days. At the research station, scientists extract tiny venom glands of various cone snails. It's a laborious process and difficult work. Powerful microscopes reveal a close-up look at the snail's barbed weapons. The mollusk's arsenal includes dozens of tiny harpoons. The barbs are tethered to their body and packed with enough venom to paralyze or kill their prey. Cone snails are indeed one of nature's most brilliant and deadly designs. In Queensland's largest city, Xenome utilizes cutting-edge technology to extract and synthesize the venoms of cone snails and other highly poisonous animals. One of Australia's deadly killers, the funnel web spider is also a potential source of new drugs. Its poison can be milked by gently stimulating the animal. Wearing up and exposing its large fangs, the spider discharges a lethal venom. Principal scientists at Xenome combine skills in genomics, chemistry and pharmacology in the pursuit of medicines based on animal toxins. The researchers have a particular interest in cone snails. The poisons of these beautiful mollusks are becoming the holy grail of new drugs. The toxic molecules or peptides of cone snails work by disrupting communications between different cell groups. By blocking these transmissions, conotoxins can effectively treat a wide variety of ailments. They've got many hundreds of different peptides and what we do is take out one or two and isolate them, work out their activity, synthesize them chemically and then we can test them in people. Venoms research has a very bright future, we believe, because it's got the potential to treat diseases that are presently untreatable. We can really now start to get very excited about the potential of these to treat a much wider range of disease. Depression, epilepsy, autoimmune diseases and acute pain are only a few of the areas in which cone snail venoms appear to hold great promise. Scientists at Xenome have isolated peptides from the venom of nearly a hundred species of cone snails. Remarkably, their toxins are far more potent and effective than morphine and other opiates. And best of all, they're non-addictive. The future of this research is pretty exciting. The main reason I do this work is to discover new things. As a traditional chemist, we used to design new drugs from scratch. Every time we work with a venom, we discover a potent new molecule with potential drug use. It's fantastic. To find many of the ocean's deadliest animals, you have to travel to some remote places. One of the most remote is Papua New Guinea. There is no better place in the world to find the sea's most venomous creatures than Papua New Guinea. Poised near the Earth's epicenter of coral reef biodiversity, the region is home to a staggering variety of poisonous animals. This nearly invisible invertebrate is the most toxic species of them all, the box jellyfish. They are responsible for more fatalities and serious injuries to humans than all other creatures in the sea combined, including sharks. Box jellyfish are a deadly presence in the tropical Pacific. The box jellyfish is, of all the different venomous marine creatures, it is the most venomous marine creature. The poisonous part of the animal is going to be a set of tentacles. And these tentacles contain specialized cells called nematocytes. It's these nematocytes that actually cause the sting and cause the envenomation. The toxin produced by the box jellyfish is a neurotoxin. It acts on the transmission of nerve impulses from the nerve to the muscle. Victims that are stung by the jellyfish will have difficulty breathing and can go into respiratory arrest. The poison can also affect the heart and go into cardiac arrest. Dr. Gary Ronay is an expert on highly toxic marine animals. His search for species like the cone snail and box jellyfish frequently bring him to places like Papua New Guinea. Oh, this is a nice one. This venom is called a neurotoxin. It actually blocks the transmission of the nerve impulse from the nerve to the muscle. So effectively, it paralyzes the muscle. As a matter of fact, in some cases, the poison is so powerful that the person is transferred to a hospital. They have to put on a breathing machine, a ventilator. It's an extremely powerful poison. Very interesting poison, too. The waters of Papua New Guinea, the Indo-Pacific area, has the greatest biodiversity of marine life in the whole world. And the greatest number of species are concentrated in very small areas. This biodiversity offers the diver a tremendous opportunity to see the most beautiful creatures in the world. Many of these are venomous and potentially dangerous, but they all play a role in the ecosystem. Many fish in the sea utilize venom, but most do so for defensive purposes only. These harmless looking creatures are marine catfish. They school together in a tightly packed group, appearing almost as a single animal. But they also have a hidden defense mechanism. They are highly venomous. Dorsal and pectoral spines are packed with a lethal cocktail. Believe it or not, these tiny fish have caused human fatalities. This strange animal is a demon stinger. Beauty may be in the eye of the beholder, but there are likely few who would find this creature attractive. It is still sometimes referred to appropriately as a ghoul or devil fish. Everything about it is odd. It can swim, but its preferred method of travel is walking. With foot-like appendages, it shuffles along the bottom. The demon stinger is part of a very large extended family named Scorpinidae, more commonly known as scorpionfish. Distributed worldwide in virtually all seas, scorpionfish come in a dazzling variety of shapes, sizes, and potency. Their venom-laden spines are very effective defensive tools. But to eat, scorpionfish rely mostly on camouflage and lightning-quick speed. Some species are highly territorial. There is no room on this reef for two male scorpionfish. After a prolonged match of nose-to-nose posturing, the two adversaries prime themselves for a fight. After locking on his foe, both animals rest. But after a few minutes, the jousting continues. This contest can last for hours. Not all scorpionfish are drab or ugly. Several members of this family are very striking animals. Their finery has inspired many names, such as turkey, lion, or zebrafish. Like most scorpionfish, their dorsal and pectoral fins are loaded with poison. Venom sacs at the base of their spines discharge a potent toxin at the slightest touch. Favorites in the global aquarium trade, many hobbyists have learned firsthand that this is one beautiful fish that you do not want to handle. This gruesome fellow is a stonefish, the most venomous fish in the sea. An envenomation from a stonefish or any of its related fish, any of the scorpionfishes at all, is extremely painful. A colleague of mine was envenomated by a stonefish. So we had to race him off to the first aid and get medical attention. So I know firsthand just how much pain a person can experience from a stonefish, almost to the point where you lose any rational thinking. The way a stonefish envenomates you is the physical pressure of stepping on the spines ruptures the skin, and then the pressure of your foot pushing down upon the spine compresses the venom sacs and the venom gets into you. This colleague of mine who was envenomated by a stonefish, and the intense pain I can imagine someone who didn't have the same strength of character as he did, may well have wanted to end their life rather than continue experiencing the pain. At the Australian Institute of Marine Science, Dr. Lyndon Llewellyn studies marine toxins and the animals that produce them. Australia, with a much larger population than New Guinea, bears the brunt of serious envenomations in the tropical Pacific. If you're interested in venomous animals, Australia is a paradise. We have some of the most venomous mollusks in the world, some of the most venomous jellyfish in the world. People shouldn't get the wrong impression that getting out of bed in the morning and going for a swim is a dangerous thing to do. Envenomations and fatalities and poisonings from marine animals are rare. Probably rarer than car accidents. Many jellyfish are poisonous, but on a tiny island in the South Pacific, this species evolved to survive in fresh water and lost its venom. In the Western Pacific lies a vast region known as Micronesia. It is not a singular country or island, but rather an immense oceanic territory that contains over 2,200 islands. Collectively, they span an area greater than the landmass of the continental United States. The tiny country of Palau is located on the far western fringe of Micronesia. Like emerald jewels in a turquoise sea, its massive lagoon is sprinkled with picturesque islands. One of the most compelling underwater ecosystems here is not part of the ocean. In the thick jungle of one of Palau's rock islands exists a strange aquatic phenomenon. Seismic upheaval caused a small portion of the lagoon to become trapped in the center of the island. This eventually isolated the lake from the surrounding ocean. Jellyfish Lake is a brackish lagoon that is home to over 100,000 non-stinging jellyfish. A few species of fish and two types of jellyfish adapted to the decreasing salinity, evolving certain unique characteristics. Most importantly, the invertebrates lost their venom. Over the millennia, the jellyfish developed a symbiotic relationship with algae. Algae is sustained by the energy of the sun. The plants live in the body of the jellyfish and provide sustenance to their mobile hosts. The jellyfish carry the algae around the lake, following the sun's rays to maximize production of new plants. It's an unusual yet productive alliance of two very different species. Unlike their marine counterparts, these animals have no use for venom. They initially had no predators and didn't need to sting their food, so evolution eventually relieved them of their weapons. They're perfectly safe to touch. But another marine predator followed them into the lake. It's unclear how or when they arrived, but unlike the jellyfish, these anemones did not lose their ability to sting. Ironically, the jellyfish are now prey to the venomous anemones. To feed, and especially to avoid being eaten, most animals rely on some form of weapon or specialized behavior. Most mollusks hide behind thick shells of armor. Other animals, like this pygmy seahorse, utilize camouflage to conceal themselves. Pipefish, a close relative of seahorses, mimic sea fans or corals. Some creatures take shelter in deep burrows, while a few even bury themselves completely in the sand. A number of species also work together to fend off attackers. In this dangerous realm, many animals form surprising alliances. Certain crustaceans are protected by sea cucumbers, jellyfish, or slugs. They catch rides with their larger, mobile hosts, who also stir up the bottom to reveal tasty morsels of food. In addition to meals and transportation, these shrimp have another deterrent to avoid predation. Nudibranchs are poisonous. If it weren't for their small size and inconspicuous habits, these sea slugs would be star attractions of the reef. Like their cousins, snails and bivalves, nudibranchs lack a protective shell. They don't need one. Any creature foolish enough to ingest a nudibranch would probably do so only once. Sea slugs are highly distasteful or even poisonous. Bright colors and markings serve notice that their flesh is extremely noxious. But they are not naturally toxic. They actually steal their weapons. Many nudibranchs are immune to the venom of stinging hydroids and anemones, their favorite foods. The venomous cells of their prey are transferred to fleshy appendages on their backs called serrata. When attacked by a predator, the stolen toxins are used to repel the attacker. This is a rare example of the use of an offensive weapon of one animal by another. Thievery and venom seem to work for these sea slugs. They have very few predators. Sea urchins utilize needle sharp spines to dissuade predators. But their defenses pack an extra punch. Tissue surrounding their spines is highly toxic. Fire urchins are appropriately named. Contact with their spines can inflict pain worse than a third degree burn. Damselfish, crabs, and shrimp find refuge in the stinging tentacles of anemones. Although deadly to many fish, anemones provide shelter to a select group of tenants. These vividly colored clown anemone fish make their homes in the stinging tentacles of their fish-eating host. They acquire an immunity by continually covering themselves with mucus secreted by the anemone. This in turn stimulates the anemone not to fire its stinging barbs. Curiously, anemone fish are all born as males. When the need arises, a male will change sex. If a dominant female dies, the largest male changes sex and takes her place. And the largest of the remaining males becomes its partner. There are countless ways to earn a living and protect oneself in this undersea community. And the use of venom remains one of the most effective tools for survival. Tropical reefs and mangroves where sea snakes and other venomous marine animals live are being destroyed at an alarming rate. Coastal development, overfishing, global warming, and disease are all taking their toll. The collection of cone snails for the shell trade is also increasing. Millions are sold annually for as little as a few cents each. To date, there are no countries which monitor the collection and trade in ornamental shells. Other venomous animals like jellyfish and many species of scorpionfish are also declining in numbers. We can only speculate on the lost opportunities for new medicines should more species become endangered or extinct. And as most of these animals are predators, it is difficult to gauge the impact on the marine ecosystem should they continue to disappear. They may be key pillars in the undersea food chain. Sea creatures produce some of the deadliest venoms in nature. And although they do injure and occasionally kill humans, they hold enormous potential in the development of powerful new medicines.