These powerful predators have one thing in common. Venom. A lethal poison designed to defend, capture, and kill. The Gila Monster. Dossel, but deadly. It is one of only two venomous lizards in the world. Unlike a snake, it does not have fangs. The Gila Monster has to chew to release its venom. Although we tend to think of venomous animals in terms of what they can do to us, their poison is intended for other victims. In nature's battles between predator and prey, venom is the ultimate weapon. Nature is made possible by the Corporation for Public Broadcasting and by annual financial support from viewers like you. And by Canon, providing the power of imaging to express your visions at home and work. And by Ford, maker of Ford Expedition. The full-size sport utility that can seat up to nine and can tow up to 8,000 pounds. The new Ford Expedition, the only way to get there. Every day, when this man goes to work, he has the potential of saving a life or losing his own. I was struggling to breathe, struggling to stay alive with no thoughts of death. But when finally I did stop breathing, it was a mind and body separation. I was being watched by myself from up in the corner of the room as I was taken from the gurney to the iron lung and put in the iron lung. During that period, I was unconscious, but I was observing what was going on and felt what was going on. And then when I came back to consciousness, I realized that no one should fear death. It's such a relief. That was the near-death experience of a man who had been bitten by a cobra. The man is Bill Host, founder and director of the Miami Serpentarium Laboratory since 1946. Host has survived many venomous snake bites during his long career, a remarkable 162 times to date, more than any other person. He spends every day in close contact with poisonous snakes. Host works with about 400 snakes from 30 different species, including one of the deadliest, the Siamese Cobra. Capturing a venomous snake requires great concentration and very quick reflexes. These snakes will bite if given the chance. When your mind wanders or there's distraction, that's when it can happen, because the snake is always on the defense. I have no fear in the work I'm doing, and if I did, I'm sure I couldn't continue it. He can do almost anything. It's amazing. Host has been working with snakes for most of his life. In this archival footage, he's trying to capture a King Cobra. Just one bite has enough venom to kill 100 people. His job is certainly one of the most dangerous on Earth, but it has a very important purpose. Ironically, the treatment for snake bite is made from venom itself. But first, someone has to extract the venom. Bill Host is the only one in the country who supplies the venom to produce snake bite antidote, called anti-venom. Host collects venom from about 30 snakes a day to meet the demand for anti-venom. Many people think I'm crazy for collecting venom. I believe snake venoms have a great potential in medicine, the treatment of different diseases, and of course for anti-venom, to treat snake bite. So how has Bill Host survived so many deadly snake bites? In an unusual experiment to build up immunity, he regularly injects himself with venom. Since I started back in 1948 with one venom, the Cape Cobra venom, I've added different species as years went on, to now I use 32 different types of venoms. And that I'm sure has helped pull me through all these serious bites. As day turns to night, a rattlesnake emerges from its hidden lair. This is a perfect hunting machine, possessing nature's top-of-the-line equipment. Darkness cannot protect its prey, because the snake can detect the heat radiating from its body. The predator approaches in silence, enabling it to get extremely close to the unsuspecting victim. And it strikes with lightning speed. The snake has just injected venom, a lethal weapon which empowers those who possess it. A surprising array of predators and prey use venom for attack and defense. This is chemical warfare. The weapons used to deliver venom come in every imaginable shape and size. Scorpions use their tails to inject venom. They squeeze the poison out of glands and through the stinger. They reserve their venom for victims that are struggling too much, or those that are too large to capture without poisoning them first. Venoms are not all alike. The scorpion's poison kills mainly by destroying the victim's nervous system. Food is scarce in the desert, and competition for it is fierce. The winner of this territorial dispute depends on size and strength, not venom. The scorpions are resistant to their own poisons, so the combatants rarely waste their precious toxins on each other. These two are evenly matched, so there's no winner or loser in this desert combat. But just because an animal is venomous does not mean it is invincible. In the Kalahari Desert, a scorpion may be the victor one moment and the victim the next. During the intense heat of the day, if there is no shade around, they create their own by digging underground. This cool hideaway is good protection from the burning sun and from predators. The mongoose is one of the few animals that can pick a fight with a scorpion and win. The adults are partially immune to the venom, but the youngsters are still at risk. The scorpion will make a tasty meal, if they can catch it without being stung. Under the watchful eye of their mother, the youngsters are allowed to test their skills. It's a dangerous game, but the pups have to learn by experience. Eventually, the youngster is able to disarm the scorpion. There is an enormous variety of venomous creatures, insects, spiders, reptiles, and amphibians, but there is only a handful of mammals armed with poison. The short-tailed shrew, one of the most common mammals in North America. It hunts for dune bugs, but it doesn't kill them right away. The shrew keeps the bugs in storage. Its toxic saliva paralyzes the victims, keeping them alive but immobile. This specialized venom is very important to the shrew's survival. Its high metabolism requires it to eat frequently throughout the day. It keeps this live food well hidden underground to prevent other shrews from raiding the well-stocked pantry. Unlike mammals, most of the 30,000 species of spiders are venomous. They have a variety of ways to capture their prey. Some build webs. Others lie in ambush. Some have a style all their own. A fresh leaf is a good place to find insects and mates, but this jumping spider has some competition. Each spider tries to claim this prime real estate, not by fighting, but by signaling to each other with their legs, waving them around in a ritualized series of movements. Then the wrestling match begins. There is actually little force involved. Each male is displaying to the other, trying to get his opponent to back down. The intruder finally retreats. The spiders don't waste their powerful venom on a minor dispute with a neighbor. They have a more important use for it. Jumping spiders rely on stealth and secrecy to capture their prey. Like a cat, it stalks quietly and slowly until it's close enough to pounce. With the element of surprise, this spider can even kill something that has venom as powerful as its own. One wrong move and predator could easily become prey. In the tropical rainforests of the Philippines, spiders have many other tricks to outwit their enemies. When two venomous animals face off, technique is of the utmost importance. The spitting spider has feeble eyesight. It finds its way in the world by touch. This delicate spider investigates a potential meal very carefully. The other spider could kill it if it became aware that it was being sized up. The spitting spider uses its venom in a unique fashion. It spits out sticky threads to ensnare the victim. This specialized secretion captures and poisons at the same time. The secretion is part glue, part venom. The glue immobilizes the prey. The venom penetrates its body. Then the spitting spider will bite to inject more venom, poisoning its prey from both inside and out. Their long legs make them expert wrappers. The silken body bag makes the meal easier to carry home. Most predators have to search for their food. Some wait till their prey wanders by, but a few can tempt their prey to come right to them. This Australian death adder is searching for a good place to set a trap. Rocks and twigs will help to conceal it from unsuspecting passersby. Then all it needs is a little patience. The adder blends in with the scenery. Then it makes its move by wiggling the tip of its tail. This worm-like decoy lures hungry prey. The worm might just be too good to be true. Ambush is only one method a snake uses to capture prey. In a bleak environment, a predator can only wait so long for a meal to come by. Diamondback rattlesnakes are the largest venomous snakes in the United States. After a winter of hibernation, this western diamondback emerges from its den, hungry and ready for desert patrol. The snake detects movements of prey through the ground, smells with its tongue, and senses the heat radiating from its body with special organs. The victim may escape, but it won't get far. It will only take a few moments for the venom to work. The snake's venom attacks the prey's nervous and respiratory systems. It also begins to break down the body, starting digestion even before the snake swallows it. The coral reef, undeniably one of the most magnificent spectacles in the natural world. It is also one of the most deadly. The reef may appear peaceful and serene, but it's actually in a state of constant warfare, chemical warfare. Many of the reef's creatures are rooted to the spot. They can't go out hunting for food, but have to wait for their prey to arrive on the fortunes of the current. They do all they can to increase their limited mobility by reaching out into the surrounding waters with an ingenious capturing device, the tentacle. They grab at anything that swims or floats by. Some are capable of capturing and eating fish. Others feed on small microorganisms. These tiny sea plankton, some smaller than a penhead, provide a perfect seafood meal for the reef community. But the tentacle doesn't just capture prey, it also kills it in a bizarre but very efficient method of attack. The tentacles respond to touch, but it's how they respond that is so amazing. The secret lies on the surface of the tentacle. These are not hairs, they are stinging cells. Each cell contains a stiletto-sharp hollow thread which is shot out in a fraction of a second. The cells fire like a barrage of microscopic harpoons. After piercing the victim, venom flows out through the tip, crippling the prey. This method is so successful it's found all over the reef. But like most weapons, what's good for offense is often just as good for defense. Poisons released from the reef's inhabitants keep many predators at bay, but these creatures also have other enemies to worry about, each other. Some of their foes are just neighbors trying to claim more real estate. Coral is a living colony of animals. As they reproduce, there are new members to add to the community, requiring more space. If there is another colony next door, the two will have to fight for the property. The war takes place at the boundaries of the colonies, and both sides may suffer casualties. The only signs of this conflict are these faint white scars at the reef's edge. The reef's poisons can be used to capture food or to protect itself from intruders. Throughout the oceans, chemical warfare plays a major role in attack and defense. The master of disguise, the octopus. But that is not its only means of protection. Octopi also have venom. So effective at killing prey, it can also be used for defense. This Australian blue-ringed octopus possesses venom so potent that one bite would paralyze ten people. But the main target of their venom is crabs. It sprays its poisonous saliva into the water. The crab will absorb the poison and become paralyzed. This octopus doesn't need a disguise. In fact, it advertises itself instead. Bright blue colors warn its predators that it packs a lethal punch. Sea slugs have the same idea. But they don't have any poisons of their own. They have to steal their ammunition. Sea slugs eat the tentacles of coral, but they don't get stung. These crafty thieves ingest the coral stinging cells and then pass them unharmed to the outside of their bodies. They can now use the stolen venom for their own defense. Unable to escape or hide, plants are especially vulnerable to attack. Some insects are very beneficial, pollinating as they feed. But others just feed and feed and feed. Over the course of evolution, plants have had to develop a counterattack. These leaves appear to be harmless, and to a beetle they are simply irresistible. But as soon as the leaf is damaged, a poisonous sticky latex oozes out. It's enough to make even the hungriest beetle change its mind. In nature, chemical defenses are used only as a last resort. Many species use warnings to prevent unnecessary skirmishes. Some animals are quite blatant about their potential danger. Others seem harmless enough. This newt has a very powerful defense, although it prefers to avoid confrontation. When the skunk gets too close, the newt has to change tactics. Since the camouflage isn't working, it now tries the opposite extreme and puts on a real show. Many amphibians have poisons in their skin and ways to advertise it. For this newt, a simple push-up reveals its bright orange underbelly, announcing that it would be a very noxious mouthful. The skunk gets the message loud and clear. Advertising your toxic wares is a good deterrent if it can be seen in time. This non-poisonous garter snake has just shed its skin. The new membrane which covers its eyes is still soft and milky. It can smell the spotted salamander, but it can't see the bright yellow warning. At first, it seems the salamander is defenseless, but its warning is not a bluff. It can back up its threat. As the snake tries to get a good grip, the salamander's sticky defense starts oozing out. Amphibians have secretions which can cause a variety of problems for their predators, a bitter taste, paralysis, or in some species, even death. In this case, the snake's jaws are getting stuck together. The salamander has to keep calm and wait. It stays still to prevent injury while the snake struggles. Eventually, the snake realizes it's made a big mistake. Unharmed, the prey can go on its way, having only been delayed a little while. The predator will soon recover from his ordeal, but this encounter is one lesson this snake won't easily forget. Even snakes need to defend themselves from time to time. Rattle snakes have a unique way of warning others to keep away. On the prairie, this prevents the snake from being trampled to death. For a snake lying low in the tall grass, a warning will be more effective if it relies on being heard, not seen. Though it can't hear its own rattle, others get the message to keep their distance. The rattle is made of dead skin. It becomes a noisemaker when the snake shakes its tail. All kinds of snakes shake their tails when they're excited, even non-venomous ones. These highly venomous bull snakes wiggle their tails in the frenzy of a fight. Since they have no limbs to wave about, if a snake has to shake something, the tip of its tail is its only option. The rattlesnake has just taken this very natural behavior one step further and put the tail to work. Often in the chemical arms race, whenever one species puts up a defensive shield, another one comes along to destroy it. This red milkweed beetle has solved a sticky problem. Slicing through the leaf's midrib, it cuts off the flow of the viscous poisonous latex into the veins. This vein drain deactivates the plant's defense. The beetle then heads for the outer edges of the leaf, where poison can no longer stop it from enjoying a meal. Some plants make it harder for insects to get past their defense. The prickly lettuce plant has spines, which discourages some foragers from nibbling. The hedge-looper caterpillar has no trouble disabling these weapons. It just eats them. But the plant still has poison to bring to its defense, arranged in a very complex network of veins. One cut won't do the trick this time. The cabbage looper attaches itself in the center and then cuts into the leaf as it swings back and forth. It moves in a very precise arc, making tiny incisions along the way. It continues this microsurgery until every vein is severed and the latex is released. It has to be quick to stay ahead of the poison. Any latex that sticks to the caterpillar has to be removed before the gooey mess hardens. Now that it's stopped the flow of latex, the cabbage looper is free to eat without any poisonous interruptions. Perhaps the most bizarre way of outsmarting a plant's defense is that of the tortuosid moth caterpillar. This plant has very toxic leaves, but the poison is only activated by sunlight. All an insect has to do is to prevent the sun from reaching the leaves. It's simple enough for this caterpillar. It attaches silk lines to the leaves, binding them together. Then it pulls them into a sunshade. The caterpillar can now eat safely inside its shady nook. Some insects don't try to avoid or deactivate a plant's poison because they steal it for themselves. One of the most infamous thieves is the caterpillar of the monarch butterfly. It makes a large incision into the leaf's midrib, blocking the major latex canal. But some of the latex seeps out in the process, which the caterpillar eats along with its meal. They are partially immune to the poison. They can now turn the plant's defense into their own, storing the noxious chemicals in their bodies. As they turn from caterpillars into butterflies, these insects will change greatly. But they'll retain all the poisons they've accumulated, nibbling and thieving. Thank you so much for watching. When the butterflies make their epic migrations from Canada to Mexico and back again, they journey relatively undisturbed, thanks to their chemical armory. But this story has a strange twist. The plants develop poison against the monarch caterpillar, and the caterpillar steals the poison for itself. But then the assassin bug enters the picture. This bug has found a way to get past the poison. But what one bug has, another one wants. The squabble ensues over the caterpillar's body. The caterpillar's poison is on its skin, so the bug just pierces through it. Now, bypassing the toxins on the outside, it sucks up the insides. The foothills of California's Sierra Nevada mountains, the scene of tactical warfare. It's springtime, and many species have been hiding out waiting for the winter to pass. This northern Pacific rattlesnake hasn't eaten for months. After emerging from hibernation, it sets out looking for a meal. The hungry snake knows just where to get it. But these California ground squirrels have faced this kind of enemy before. They have a battle plan. Their first concern lies below in their underground nursery. Here there are helpless pups of all ages. The snake hunts by searching for burrows where youngsters may be hidden. Pups are its favorite food. It won't be easy for the snake to get past these guards. The squirrels gang up, surround it, even kick sand in its face. Using their tails like a matador's cape, the squirrels try to buy some time, while one member of the colony evacuates the nursery. The adults can afford to be bold. They're faster than the snake, and partially immune to its venom. But it seems the snake may be using all this activity as a clue that the squirrels have something to hide. It heads straight for the nursery. The squirrels' teamwork has paid off, and the rattlesnake must hunt elsewhere. In this battle, strategy is just as important as weaponry. The squirrels' tactics involve mobbing and harassing. The snake may be using those very behaviors to decide which burrows to target. Though unsuccessful this time, the rattlesnake will find other victims. Venom reaches the peak of its power in snakes, and nowhere is this more evident than in Australia, where snakes rule supreme. It is home to the 11 most poisonous snakes in the world. This is the most deadly of them all, the small-scaled snake. With one bite, it could kill a quarter of a million mice. The mulga's venom is not as potent, but what it lacks in quality it makes up for in quantity by injecting a massive dose. Its venom appears to be different than the other Australian snakes, affecting the muscles of its prey instead of the nerves. It causes rapid paralysis. The killing force of these snakes far outweighs what they need to survive. No one knows why they have evolved such excessive power. Though most snakes live on land, many have taken to the seas. Sea snakes are completely at home in the water. Some types can stay submerged for two hours before coming up for air, and their paddle-shaped tails are designed for swimming. Their venom works quickly, preventing fast-moving prey from escaping and hiding in the reef. This one's hunting for eels, constantly checking their burrows as it swims by. Like all venomous creatures, it uses its poison only to capture food or in self-defense. Most fish rely on speed for defense. Some are slow, but deadly. The puffer fish seems like an easy target, but most predators avoid this toxic entree. This poisonous pisces, also known as fugu, is considered a delicacy in Japan. It is prepared very carefully. The stingray has a loaded weapon under its tail, a spine primed with venom. And under the fluttering fins of a lionfish is an entire arsenal of poisonous spines. This ostentatious display is a very clear warning that it would be best for a predator to select another fish for dinner. This big fish eats little fish, one by one. But one little upstart is brave enough to pester the lionfish. It's a baby puffer fish. It torments its victim, nipping pieces out of its fins. Losing patience, the lionfish snaps it up and spits it out. The toxic mouthful is free to continue harassing the lionfish. Venom, one of nature's most versatile tools of survival. To find out more about nature, visit us on the PBS home page at the address on your screen. Nature is made possible by the Corporation for Public Broadcasting and by annual financial support from viewers like you. And by Canon, providing the power of imaging to express your visions at home and work. And by Ford, maker of the 1997 Taurus, a unique combination of American heritage and innovation makes Taurus an automobile its owners love to talk about. Taurus by Ford. I'm not bragging, but I've been bitten by poisonous snakes over 162 times. And I guess what I should be satisfied about is that I'm still here to tell you 162 times. Want me to tell you a story? One of the stories? A little boy was bitten by a coral snake in Venezuela, and this isn't good. Look, look, look, look. But the snake is clever. Oh, they'll catch him. Please, he's got him. He got him. He got him right in the nick of time.