"Life must battle to survive." "In four billion years of hunting predators have become better at killing." "But their prey have become better at escaping." "These escalating battles have shaped every living thing." "Such "arms races" produce ever-improved weapons... and strategy." "In these races, the price of failure can be extinction." "But today's animals are the triumphant survivors of a four-billion-year war." "For them, the eternal arms race continues." "For millions of years the cheetah has largely preyed on one animal... the gazelle." "Cheetahs are master gazelle killers but gazelles are superb at escaping cheetahs." "The creatures are locked in an evolutionary arms race a race for survival, that has no end." "It has made them the fastest and second-fastest animals on the African plains." "Cheetahs are swifter in a straight line but gazelles can turn more quickly... and have great stamina." "Gazelles frequently escape and only the fastest cheetahs make regular kills." "The mother's physical qualities and much of her behavior-- both crucial for hunting-- pass to her young in the form of genes." "The genetic code is a blueprint for making a successful cheetah." "But the genetic recipe for the perfect hunter is unachievable, because the gazelle's genes are also updated every generation." "This genetic arms race continually reshapes both animals." "Arms races between predators and prey affect the lives of all creatures." "There is tension whenever hunters and hunted come together." "The shape and behavior of all these creatures is molded by the need to hunt or escape." "The pressures that shape prey have left the gazelle agile, fast and vigilant-- qualities useful against all predators, even the unexpected." "The baboon has no answer to the speed and agility of the adult gazelle." "The mother's successful genes will live on in her offspring." "Most prey are under siege from all sides and must balance the risks of attack from many different predators." "Staying alive is a juggling act." "In Australia's Northern Territory sea eagles can snatch fruit bats from treetops." "The best defense against these birds is to hide in the middle of the tree." "But this is the worst place to hide from snakes." "Vines and branches are highways for the carpet python." "Low-ranking bats, pushed to the edge of the colony are in greatest danger." "If their excellent sight gives them early warning they move to branches where snakes cannot reach them." "Safe havens from snakes and eagles often overhang rivers." "But when water levels are high this leaves them vulnerable to another predator." "The noise of roosting bats is a dinner bell to a master opportunist." "Crocodiles are ambush specialists grabbing whatever they can." "Their strategy is hard to anticipate or prepare for." "Having escaped its main predators the bat is exposed to another." "Crocodiles have been shaped by a more ancient arms race-- probably the oldest one of all-- the race for size." "The principle is simple:" "Become large enough to eat anything and too large to be eaten." "This same force has helped shape the world's largest land animal." "Elephants don't tackle prey but their size gives them protection from predators." "The ancestors of modern elephants were far smaller and regularly fell prey to big cats." "Rather than become fast like gazelles, elephants grew big." "These days, few cats could tackle such a large and powerful animal." "For hunter and hunted alike, being big is a winning formula." "Again and again across the animal kingdom large size has evolved in both predators and prey." "But there's a price to pay for being large." "It takes a lot of energy to pack on the pounds and carry the weight." "A few animals only grow big when it counts." "This tadpole doesn't waste energy growing protective bulk when the pond is safe." "Instead, it diverts all its energies to becoming a North American tree frog..." "Unless predators arrive at its pond." "Dragonflies themselves are harmless to tadpoles but the eggs they lay under the water's surface will hatch into something deadly." "Dragonfly nymphs are more than a match for a poorly streamlined tadpole with a body designed for eating." "The tadpole's chances of escape are slim." "But only the first tadpoles are easy." "Things in this pond are about to change." "This tadpole's life is over but its death will help its siblings to survive." "The mangled prey oozes body fluids containing special alarm chemicals." "These diffuse through the water to its relatives activating genes that trigger an extraordinary transformation." "Over the next few days the tadpoles pack on weight and grow large red tails." "Remarkably, these large, red-tailed tadpoles are the same species as the thinner, brown-tailed variety." "But the red-tails are the antipredator version." "The larger tail gives them greater acceleration making them very hard to catch." "Their color is more of a mystery." "Red may be a warning to predators that these tadpoles are too fast for them." "Red-tailed tadpoles take longer to become frogs but it's better to arrive late than never." "Sophisticated defenses like this evolved from millions of years of conflict between predators and prey." "Such battles have ancient origins." "Over 500 million years ago, only the oceans harbored life." "Predation was a slow and passive affair." "Jellyfish caught plankton by simply bumping into it with sticky tentacles." "On the sea floor anemones collected food in much the same way." "Anchored to rocks these creatures sifted the currents for microscopic prey." "Animals still alive today, such as anemones and flatworms give an idea of what this world might have looked like." "With no quick predators on the scene this was life in the slow lane." "There was no need for speed or protection." "There were no hard parts;" "neither teeth nor jaws had yet evolved." "The only body designs were based on soft and spongy sacs of cells." "But the world was about to change." "A new kind of gene organized the sacs of cells into segmented bodies." "Predators with fins, jaws and complex eyes evolved." "Now animals could hunt their food." "Predation had arrived." "Evolution went into overdrive." "Armor was the next great invention as calcium from water and stone was transformed into protective shields." "Many of the seashells still familiar today evolved in just a few million years." "Scales, acting like chain mail, were a good defense." "But predators fought back with improved jaws." "Some scales evolved into spines which prevented jaws from getting close to the body." "Bizarre animals like the spine-covered Hallucigenia are now lost in time." "Others are still around today." "Soon, even predators were using elaborate shields to protect themselves from larger predators." "But armor is costly to make and cumbersome to carry." "These clunky designs were vulnerable to a new generation of speedy hunters." "Improved senses allowed animals to swap armor for lightweight protection." "Prey could now detect approaching predators and simply leave." "With the arrival of senses, delicate escape artists found a place alongside heavily armored creatures." "This ancient era, the Cambrian period was the cradle of complex animals and the birthplace of many of life's triumphs." "Among them were the ammonites." "Adjustable buoyancy offset the weight of their armor." "They were mobile and well protected." "Efficient predators, they became the dominant creatures for a hundred million years until the arrival of a predator with jaws." "Ammonites were outgunned." "Their defenses crumbled as fish exterminated them from shallow seas." "Relatives of the ammonites survived in the ocean depths where few fish could follow." "Today, the nautilus is the last shelled relative of the ammonites and has changed little in 300 million years." "The nautilus skulked in the deep while fish flourished above, dominating ancient seas." "But the fish had a new challenger in the shallow waters." "Squid, cousins of the ammonites, lost their shells and evolved the speed to hunt and escape." "To this day, they take on fish at their own game." "Below, on the reef the octopus, also a modern relative of the ammonites has a defense against sharp-eyed fish." "Fish rely on good sight for hunting but the octopus is a master of disguise." "Its rapidly changing camouflage allows it to vanish in an instant." "The eyes gather information about the pattern of the reef the suckers about its texture." "From this palette the octopus can paint the reef across its skin and fool fish eyes..." "most of the time." "The camouflage can deceive us and it's probably more deceiving to a fish." "After all, octopus camouflage has been finely honed by evolution to exploit shortcomings in fish vision." "An octopus can still be seen when moving and when its camouflage is switched off." "Just as in any arms race neither side has total dominance." "As a last resort the octopus reaches into its magician's hat and pulls out a cloak of ink." "The long war with fish has produced an octopus with even greater magic-- the mimic octopus of Indonesia." "It lives exposed on open ground and survives not by mimicking its surroundings but the other creatures that live here." "Snake eels are slippery customers and few fish eat them." "So the octopus mimics them, hiding its true identity." "Sea snakes are highly venomous." "Fish stay well away." "The octopus is a remarkable match." "As sea snakes are so dangerous even a suspicious fish won't risk a fatal mistake." "The slightest scratch from the lionfish's spines can kill." "Its fins shimmer arning." "The movement is matched perfectly by the mimic octopus." "The cuttlefish is a relative of the octopus so it's hardly surprising that it has excellent camouflage and uses this to travel unnoticed by fish." "Away from the bottom, it even takes on the shape of weeds to break up its outline." "But a cuttlefiso use its skin to hunt." "A creature from the imagination could hardly be more alien." "The display seems to mesmerize victims." "Unlike a hunting tiger stuck with its stripes or a leopard that can't change its spots the cuttlefish attacks in many disguises." "A skin that can switch between moving patterns that confuse and astonishing camouflage to deceive must count among evolution's greatest triumphs." "It could be that cuttlefish with their extraordinary skin and superb eyesight have edged ahead of fish in this visual arms race." "The scallop only has light-sensitive cells gathered in blue pits, but even these can save its life." "Add a simple lens, and the owner can resolve detail." "Eyes are such good tools for escaping and hunting that they have evolved many times into a diverse array of seeing machines." "These eyes belong to Portia, a jumping spider and they're her main hunting tools." "Portia stalks with a most unspider like walk part of her disguise when approaching prey." "She hunts other spiders, identifying them by sight." "Pick the wrong spider and Portia could end up as lunch herself." "Argiope has been hunted by Portia for millions of years and now has a few tricks to deal with the deadly menace." "The web is too thin to take the hunter's weight so Portia tries to lure her victim to the edge by twitching the silk, mimicking a struggling insect." "But Argiopeis wise to the trick and bounces violently a tactic that could catapult Portia from the web." "Portia seems defeated." "But the master hunter only appears to give up." "In fact, she's taking a lengthy detour." "Portia loses sight of her prey for a time but still emerges exactly where she needs to be... right above Argiope." "The predator takes careful aim then lowers herself towards the unsuspecting prey." "This mission only seems impossible." "Fatally bitten, Argiope will take time to die." "Portia waits;" "her keen vision has triumphed." "Sharp-eyed predators are everywhere so potential prey like moths lie low." "Their ancestors millions of years ago were active by day, but as birds multiplied moths fled to the night." "For millions of years, moths had the night skies to themselves and they filled them." "But around 50 million years ago one of the greatest arms races of all time began." "The ancestors of bats were small mammals which pounced on insects." "Flying was a ticket to the vast larder of moths that filled the night skies." "But how could they find small, fast-moving prey without sunlight?" "Bats use their ears." "They emit high-intensity pulses of sound... then listen for echoes bouncing back." "Their brains process these reflections into a three-dimensional image-- an accurate picture of their dark world." "Slowing down picture and sound gives a clearer view of each encounter." "This sonar is a brilliant weapon for finding prey in the dark making bats successful around the world." "Bats, though, didn't have it all their own way for long." "Moths evolved a counterweapon-- a simple ear that could detect approaching sonar." "An early warning allows the moth to swerve away." "As bats approach, they increase their calling rate-- for moths, an emergency cue to plummet... though not always to safety." "Many bats are superb fishermen." "It's even possible that hunting over water has become a deliberate ploy to snare diving moths." "As insects became better at detecting sonar bats required a countermeasure." "In a shadowy corner, a strange creature is stirring." "Long-eared bats have defeated the insect ear by improving their own hearing." "Instead of hunting by sonar they use their outrageously large ears to listen for the sounds of insects." "Even the tiny beat of moth wings can be filtered out from the sound of rushing water." "The bats still use sonar to avoid branches but as they approach their prey, they switch that off and enter "stealth mode."" "Now the bat steers entirely by the wingbeats of its prey but the system isn't perfect." "This bat approaches from the wrong side." "It can hear the moth, but through the leaf." "A lucky escape for the moth." "Although the bat's hearing is superb the method has yet another flaw." "If the moth stays still, the bat can't locate it." "By maintaining silence, the moth is perfectly safe." "The hunter is forced to give up." "But sooner or later, the moth must move revealing its presence." "Bats have kept pace with their prey's attempts to evade them and today the night skies are full of specialized moth killers." "To avoid them some moths are taking the ultimate evasive action." "In Venezuela, moths are escaping the night." "Active by day, theJosiamoth can avoid bats completely but instead, it must face the birds." "This brings the war full circle." "Birds are probably the predators that drove moths to the night in the first place." "But the moths returned to the day with a new trick:" "distasteful chemicals advertised with brilliant colors." "TheJosiastill has remnants of the ears that once warned it of approaching bats but they are of no use against a sharp eye." "Spit out, the moth may even escape with its life but the bird has learned a lesson." "Most predators learn quickly to associate colors with danger resulting in a world of brilliantly patterned prey." "In Oregon lives theTarichan newt." "Orange pigment is a warning that it's more than distasteful." "Each newt contains enough poison to kill 20,000 mice, or hundreds of people." "In spring they congregate to mate." "A gathering of soft-bodied creatures should be a feast for predators." "But local animals know the newts are deadly." "And those that don't are warned off by a display of its orange belly." "But why is the newt so poisonous with enough toxin to kill thousands of crows when enough to kill one would seem sufficient?" "Crows aren't the problem." "Meet the newt's nemesis... the garter snake." "Long ago, these snakes evolved a resistance to low doses of newt poison." "Their prey fought back producing more poison." "Snakes countered with greater resistance." "Predator and prey became caught in an escalating arms race." "Every generation, the snakes get more resistant and the newts more poisonous." "This arms race has now reached a ridiculous level." "The newt spends much of its energy making poison and the snake becomes paralyzed within moments of eating a newt." "To survive the meal the snake must wind down its metabolism while it neutralizes the poison." "Vulnerable to predators, it must lie still for several hours." "For the snake, it's not all bad news." "After eating the newt its tissues are saturated with toxin so it becomes poisonous itself." "The newt-eating race of garter snake is more brightly colored than its relatives elsewhere-- possibly to advertise this secondhand poison." "Poison is a great defense throughout the animal kingdom even against master predators like bobcats." "But poison is expensive to make so the hognose snake has none and just pretends." "Cats take the threat of venom seriously so a posturing snake is approached with caution." "There's meat on a snake, but one meal isn't worth dying for." "The bobcat isn't fooled for long and launches an attack." "The cat's confidence grows, and the snake switches tactic rolling onto its back and playing dead very convincingly." "The hognose even reeks of death as a foul-smelling fluid oozes from its body." "Many predators avoid corpses as a precaution against disease." "The cat's interest wanes." "But all the while, the snake is watching from the corner of its eye." "Only when the cat has gone does the snake seem to rise miraculously from the dead." "It's an incredible display of deception but where did this reptile learn its life-saving trick?" "The answer can be found in the underground nest of a hognose snake." "As soon as the eggs hatch the young snakes rush to leave the chamber." "Such a concentration of yolk and young often attracts predators." "The last to leave are the most at risk." "Just hatched, the young snakes should be an easy target for a hungry rat." "The rat moves in for the kill." "But incredibly, the snake goes belly up and shows all the death-feigning trickery of the adult." "This behavior is programmed into the genes." "There was no time for the snake to learn this trick yet it can deceive a predator from the moment of hatching." "Snakes don't always succeed." "As they improve their performance cats and rats improve their ability to see through the act." "While the snake's display deters predators other displays have evolved to attract them." "As daylight fades in Puerto Rico the waters of Mosquito Bay light up with eerie glows." "Fish shoot through the water like fireworks their outlines illuminating the night sea." "These are the most glittering waters on earth." "Like the ghosts of fish some have great length, others the flattened form of rays." "Viewed with a special camera the display is even more dazzling but the source is still unclear." "Add infrared light-- invisible to most animals-- and shapes begin to emerge from the gloom." "Turn up the infrared and lobsters can be clearly seen-- their antennae like sparklers." "It's not the large animals that are glowing but something in the water." "Each spark comes from a single- celled organism called Noctiluca that glows when disturbed." "But why should they light up?" "Noctiluca are eaten by shrimp." "But surely glowing will only attract them." "They even continue to glow once inside the shrimp." "Their light show doesn't go unnoticed by the shrimp's predators, cuttlefish." "Noctiluca's display starts to make sense." "The cuttlefish can't find shrimp in complete darkness." "The shrimp is safe as long as it stays still." "Even with pupils dilated, the cuttle sees nothing." "But if the shrimp moves" "Noctiluca sparkles and illuminates it." "Now the cuttlefish can see the shrimp." "The flashing Noctiluca, like a burglar alarm gives away the shrimp's presence." "By attracting cuttlefish with their flashing lights" "Noctiluca protects itself against shrimp." "The cuttlefish, by predating shrimp, is Noctiluca's ally." "It's cat-and-mouse, and the shrimp can't win." "If it stays still, it can't eat Noctiluca and if it moves, a glittering trail attracts cuttlefish." "For shrimp, hunting Noctiluca is a risky business." "The cuttle gets a meal, but the real winner is Noctiluca:" "Every shrimp removed makes life safer for the tiny organism." "Noctiluca's "burglar alarm" saves its life but each tiny living spark is unaware of the defense strategy programmed into its genes." "Coded into the genes of another creature is an even more elaborate display critical to its survival." "In the streams of Missouri lives the Lampsilis mussel a simple animal with an extraordinary life cycle." "To reach adulthood, its young must spend part of their lives inside a fish, the large-mouth bass." "To get there, the mussels must make physical contact-- a difficult task, as mussels don't swim." "But the bass has a weakness." "It's a voracious predator of small fish particularly darters." "Even the slightest wriggle of a darter's tail will attract bass." "Believe it or not, the "fish" on the mussel is an imitation-- a perfect replica that will lure bass within striking range." "The mussel can somehow sense approaching fish and wriggles its lure faster to entice them." "If it gets the twitching just right the remarkable likeness should do the rest." "On impact the mussel squirts its young into the bass's mouth." "These snap shut on the gills, like spring-loaded traps." "Here they stay, drawing blood from the fish until several weeks later they drop off as tiny, fully formed mussels." "Also a favorite prey of the bass are these striped shiners and some mussels mimic them." "Considering mussels are blind and have never seen a shiner the likeness is incredible." "The eyes, fins and even the stripe look just right." "Yet the mussel knows nothing of its own appearance." "These lures have evolved because bass more often attack mussels that look like fish so fishy-looking mussels leave more descendants." "After millions of years of blind evolution this process of selection has turned mussel flesh into a lifelike lure." "It takes a good imitation to fool a bass in clear water and some of them are incredible." "This darter mimic even has a mouth which gulps." "This mussel is the same species but its curious leopard print design may not find a taker and its genes will go no further." "This lure looks pretty good." "But the bass is unconvinced and turns it down." "Mussel lures are constantly improving but fish are getting ever better at recognizing fakes." "It's another arms race, and it's still creating diversity in the streams of Missouri to this day." "The battle between individuals to pass their genes on to the next generation has been shaping plants and animals since life began." "In every corner of the planet arms races are changing animal form and behavior." "Understanding arms races provides a new, dynamic view of life itself." "Plants are at war with herbivores." "Their defensive spines are countered by the elephant's toughened lips." "The acacia grows upwards to escape its attackers but its push for safety has been countered by the giraffe's long neck." "The acacia and giraffe have shaped one another." "The shape and behavior of all creatures are molded by other living things." "Nothing evolves in isolation." "Cheetahs created gazelles, just as gazelles created cheetahs and even today both are constantly changing." "Evolution never stands still." "The genes in each generation will be tested anew." "It's a never-ending race for survival." "The story of life has been and always will be a tale of genes battling to ensure their line triumphs."