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00:00Life must battle to survive.
00:21In four billion years of hunting,
00:24predators have become better at killing.
00:26But their prey have become better at escaping.
00:37These escalating battles have shaped every living thing.
00:44Such arms races produce ever-improved weapons and strategy.
00:50In these races, the price of failure can be extinction.
01:04But today's animals are the triumphant survivors
01:07of a four billion year war.
01:11For them, the eternal arms race continues.
01:15The Earnings
01:26Seat
01:30For millions of years, the cheetah has largely preyed on one animal, the gazelle.
02:00Cheetahs are master gazelle killers, but gazelles are superb at escaping cheetahs.
02:13The creatures are locked in an evolutionary arms race, a race for survival that has no
02:19end.
02:27It has made them the fastest and second fastest animals on the African plains.
02:41Cheetahs are swifter in a straight line, but gazelles can turn more quickly and have greater
02:48stamina.
02:50Gazelles frequently escape, and only the fastest cheetahs make regular kills.
03:15The mother's physical qualities and much of her behavior, both crucial for hunting,
03:27pass to her young in the form of genes.
03:31The genetic code is the blueprint for making a successful cheetah.
03:36But the genetic recipe for the perfect hunter is unachievable, because the gazelle's genes
03:41are also updated every generation.
03:45This genetic arms race continually reshapes both animals.
03:57The arms races between predators and prey affect the lives of all creatures.
04:02There is tension whenever hunters and hunted come together.
04:04The shape and behavior of all these creatures is molded by the need to hunt or escape.
04:27They're going deeper.
04:52The
05:04pressures that shape prey have left the gazelle agile, fast, and vigilant.
05:10Qualities useful against all predators, even the unexpected.
05:22The baboon has no answer to the speed and agility of the adult gazelle.
05:44The mother's successful genes will live on in her offspring.
05:50Most prey are under siege from all sides and must balance the risks of attack from many different predators.
06:00Staying alive is a juggling act.
06:04In Australia's Northern Territory, sea eagles can snatch fruit bats from treetops.
06:12The best defense against these birds is to hide in the middle of the tree.
06:18But this is the worst place to hide from snakes.
06:22Vines and branches are highways for the carpet python.
06:30Low ranking bats pushed to the edge of the colony are in greatest danger.
06:38If their excellent sight gives them early warning, they move to branches where snakes cannot reach them.
06:56Safe havens from snakes and eagles often overhang rivers.
07:14But when water levels are high, this leaves them vulnerable to another predator.
07:26The noise of roosting bats is a dinner bell to a master opportunist.
07:32Crocodiles are ambush specialists, grabbing whatever they can.
07:44Their strategy is hard to anticipate or prepare for.
07:50Having escaped its main predators, the bat is exposed to another.
08:08Their strategy is hard to prepare for.
08:26Crocodiles have been shaped by a more ancient arms race.
08:30Probably the oldest one of all.
08:32The race for size.
08:36The principle is simple.
08:38Become large enough to eat anything and too large to be eaten.
08:44This sane force has helped shape the world's largest land animal.
08:50Elephants don't tackle prey, but their size gives them protection from predators.
09:00The ancestors of modern elephants were far smaller
09:04and regularly fell prey to big cats.
09:12Rather than become fast like gazelles, elephants grew big.
09:16These days, few cats could tackle such a large and powerful animal.
09:22These days, few cats, few cats, few cats.
09:32For hunter and hunted alike, being big is a winning formula.
09:36Again and again, across the animal kingdom, large size has evolved in both predators and prey.
09:52But there's a price to pay for being large.
10:08It takes a lot of energy to pack on the pounds and carry the weight.
10:12A few animals only grow big when it counts.
10:20This tadpole doesn't waste energy growing protective bulk when the pond is safe.
10:26Instead, it diverts all its energies to becoming a North American tree frog.
10:30Unless predators arrive at its pond.
10:40Dragonflies themselves are harmless to tadpoles.
10:44But the eggs they lay under the water's surface will hatch into something deadly.
10:48Dragonfly nymphs are more than a match for a poorly streamlined tadpole with a body designed for eating.
11:08The tadpole's chances of escape are slim.
11:10But only the first tadpoles are easy.
11:22Things in this pond are about to change.
11:28This tadpole's life is over.
11:30But its death will help its siblings to survive.
11:34The mangled prey oozes body fluids containing special alarm chemicals.
11:48These diffuse through the water to its relatives.
11:50Activating genes that trigger an extraordinary transformation.
11:54Over the next few days, the tadpoles pack on weight and grow large red tails.
12:10Remarkably, these large red-tailed tadpoles are the same species as the thinner, brown-tailed variety.
12:16But the red tails are the anti-predator version.
12:24The larger tail gives them greater acceleration, making them very hard to catch.
12:32Their color is more of a mystery.
12:36Red may be a warning to predators that these tadpoles are too fast for them.
12:50Red-tailed tadpoles take longer to become frogs.
12:53But it's better to arrive late than never.
12:59Sophisticated defenses like this evolved from millions of years of conflict between predators and prey.
13:05Such battles have ancient origins.
13:13Over 500 million years ago, only the oceans harbored life.
13:17Predation was a slow and passive affair.
13:21Red-tailed tadpoles were the same.
13:25Jellyfish caught plankton by simply bumping into it with sticky tentacles.
13:31On the sea floor, anemones collected food in much the same way.
13:35Anchored to rocks, these creatures sifted the currents for microscopic prey.
13:51Animals still alive today, such as anemones and flatworms, give an idea of what this world might have looked like.
14:01Anemones still alive today, such as anemones and flatworms, give an idea of what this world might have looked like.
14:15With no quick predators on the scene, this was life in the slow lane.
14:29There was no need for speed or protection.
14:31There were no hard parts.
14:33Neither teeth nor jaws had yet evolved.
14:35The only body designs were based on soft and spongy sacks of cells.
14:41But the world was about to change.
14:51A new kind of gene organized the sacks of cells into segmented bodies.
14:59Predators with fins, jaws, and complex eyes evolved.
15:13Now, animals could hunt their food.
15:27Predation had arrived.
15:29Evolution went into overdrive.
15:37Armor was the next great invention, as calcium from water and stone was transformed into protective shields.
15:49Many of the seashells still familiar today evolved in just a few million years.
15:54Scales, acting like chain mail, were a good defense.
16:04But predators fought back with improved jaws.
16:06Some scales evolved into spines, which prevented jaws from getting close to the body.
16:18For Growth and engulfed.
16:26No depth.
16:28Bizarre animals like the spine-covered hallucinia are now lost in time.
16:30Others are still around today.
16:33today. Soon, even predators were using elaborate shields to protect themselves
16:41from larger predators. But armor is costly to make and cumbersome to carry.
16:52These clunky designs were vulnerable to a new generation of speedy hunters.
16:59Improved senses allowed animals to swap armor for lightweight protection.
17:10Prey could now detect approaching predators and simply leave.
17:19With the arrival of senses, delicate escape artists found a place alongside heavily armored
17:24creatures. This ancient era, the Cambrian period, was the cradle of complex animals and the
17:36birthplace of many of life's triumphs. Among them were the ammonites. Adjustable buoyancy
17:46offset the weight of their armor. They were mobile and well protected. Efficient predators,
17:53they became the dominant creatures for a hundred million years, until the arrival of a predator
18:00with jaws.
18:12Ammonites were outgunned. Their defenses crumbled as fish exterminated them from shallow seas.
18:18Ammonites. Relatives of the Ammonites survived in the ocean depths a few fish could follow.
18:25Today, the Nautilus is the last shelled relative of the Ammonites and has changed little in 300
18:30million years. The Nautilus skulked in the deep, while fish flourished above, dominating ancient
18:33seas.
18:48But the fish had a new challenger in the shallow waters.
18:55But the fish had a new challenger in the shallow waters.
19:02Squid, cousins of the Ammonites, lost their shells and evolved the speed to hunt and escape.
19:09To this day, they take on fish at their own game.
19:30Below, on the reef, the octopus, also a modern relative of the Ammonites, has a defense against sharp-eyed fish.
19:38Fish rely on good sight for hunting, but the octopus is a master of disguise.
19:49Its rapidly changing camouflage allows it to vanish in an instant.
19:54The eyes gather information about the pattern of the reef.
19:59The suckers about its texture.
20:01From this palette, the octopus can paint the reef across its skin and fool fish eyes.
20:09Most of the time.
20:16The camouflage can deceive us, and it's probably more deceiving to a fish.
20:22After all, octopus camouflage has been finely honed by evolution to exploit shortcomings in fish vision.
20:28An octopus can still be seen when moving, and when its camouflage is switched off.
20:47Just as in any arms race, neither side has total dominance.
20:58As a last resort, the octopus reaches into its magician's hat and pulls out a cloak of ink.
21:07The long war with fish has produced an octopus with even greater magic.
21:19The mimic octopus of Indonesia.
21:20It lives exposed on open ground, and survives not by mimicking its surroundings, but the other creatures that live here.
21:36Snake eels are slippery customers, and few fish eat them.
21:44So the octopus mimics them, hiding its true identity.
21:53Sea snakes are highly venomous.
21:56Fish stay well away.
21:57The octopus is a remarkable match.
22:09As sea snakes are so dangerous, even a suspicious fish won't risk a fatal mistake.
22:14The slightest scratch from the lionfish's spines can kill, and its fins shimmer as a warning.
22:36The movement is matched perfectly by the mimic octopus.
22:44The cuttlefish is a relative of the octopus, so it's hardly surprising that it has excellent camouflage,
22:51and uses this to travel unnoticed by fish.
23:01Away from the bottom, it even takes on the shape of weeds to break up its outline.
23:14But a cuttlefish can also use its skin to hunt.
23:35A creature from the imagination could hardly be more alien.
23:39The display seems to mesmerize victims.
23:44The display seems to mesmerize victims.
24:10Unlike a hunting tiger stuck with its stripes, or a leopard that can't change its spots,
24:16the cuttlefish attacks in many disguises.
24:18A skin that can switch between moving patterns that confuse, and astonishing camouflage to deceive,
24:27must count among evolution's greatest triumphs.
24:42It could be that cuttlefish, with their extraordinary skin and superb eyesight, have edged ahead of fish in this visual arms race.
24:57The scallop only has light-sensitive cells gathered in blue pits, but even these can save its life.
25:12Add a simple lens, and the owner can resolve detail.
25:27Eyes are such good tools for escaping and hunting, that they have evolved many times into a diverse array of seeing machines.
25:35These eyes belong to Portia, a jumping spider, and they're her main hunting tools.
25:54Portia stalks with a most un-spider-like walk, part of her disguise when approaching prey.
26:02She hunts other spiders, identifying them by sight.
26:12Pick the wrong spider, and Portia could end up as lunch herself.
26:21Argyope has been hunted by Portia for millions of years, and now has a few tricks to deal with the deadly menace.
26:28The 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.
26:45But Argyope is wise to the trick, and bounces violently, a tactic that could catapult Portia from the web.
27:01Portia seems defeated.
27:05But the master hunter only appears to give up.
27:10In fact, she's taking a lengthy detour.
27:16Portia loses sight of her prey for a time, but still emerges exactly where she needs to be.
27:29Right above Argyope.
27:36The predator takes careful aim, then lowers herself towards the unsuspecting prey.
27:46This mission only seems impossible.
27:58Potia remains the enemy of the enemy, of the enemy.
27:59It's a way for her to melt the poison.
28:00A witch in her mind, Kempe is the enemy, of the enemy.
28:01It must have been avoided.
28:02With the enemy of the enemy, she's been shot.
28:04He was dead in sight.
28:05The enemy of the enemy, the enemy of the enemy was the enemy, the enemy, and the enemy, who could,
28:07look out a little bit of dark.
28:08The enemy was aue of the enemy.
28:12And that was an attempt to kill him, and he's killed someone in the question of the enemy.
28:13Fatally bitten, Argyope will take time to die.
28:19Portia waits.
28:20to die. Portia waits. Her keen vision has triumphed.
28:31Sharp-eyed predators are everywhere, so potential prey like moths lie low. Their ancestors,
28:38millions of years ago, were active by day. But as birds multiplied, moths fled to the
28:44night. For millions of years, moths had the night skies to themselves, and they filled them.
29:01But around 50 million years ago, one of the greatest arms races of all time began.
29:14The ancestors of bats were small mammals, which pounced on insects. Flying was a ticket
29:27to the vast larder of moths that filled the night skies. But how could they find small,
29:32fast-moving prey without sunlight? Bats used their ears. They emit a lot of
29:43high-intensity pulses of sound. Then listen for echoes bouncing back. Their brains process
30:00these reflections into a three-dimensional image, an accurate picture of their dark world.
30:06Slowing down picture and sound gives a clearer view of each encounter.
30:23This sonar is a brilliant weapon for finding prey in the dark, making bats successful around
30:29the world. Bats, though, didn't have it all their own way for long. Moths evolved a counterweapon,
30:41a simple ear that could detect approaching sonar. An early warning allows the moth to swerve away.
30:54As bats approach, they increase their calling rate. For moths, an emergency cue to plummet.
31:13Though not always to safety. Many bats are superb fishermen. It's even possible that hunting over
31:25water has become a deliberate ploy to snare diving moths.
31:30As insects became better at detecting sonar, bats required a countermeasure.
31:51In a shadowy corner, a strange creature is stirring. Long-eared bats have defeated the insect ear
32:03by improving their own hearing. Instead of hunting by sonar, they use their outrageously large ears
32:10to listen for the sounds of insects. Even the tiny beat of moth wings can be filtered out from the sound of rushing water.
32:23The bats still use sonar to avoid branches. But as they approach their prey, they switch that off and enter stealth mode.
32:41Now, the bat steers entirely by the wing beats of its prey. But the system isn't perfect. This bat approaches from the wrong side.
32:50It can hear the moth, but through the leaf. A lucky escape for the moth.
33:05Although the bat's hearing is superb, the method has yet another flaw.
33:14If the moth stays still, the bat can't locate it.
33:29By maintaining silence, the moth is perfectly safe.
33:35The hunter is forced to give up.
33:44But sooner or later, the moth must move, revealing its presence.
33:49Bats have kept pace with their prey's attempts to evade them. And today, the night skies are full of specialized moth killers.
34:10To avoid them, some moths are taking the ultimate evasive action.
34:19In Venezuela, moths are escaping the night. Active by day, the joshua moth can avoid bats completely.
34:27But instead, it must face the birds. This brings the war full circle.
34:36Birds are probably the predators that drove moths to the night in the first place.
34:40But the moth return to the day with a new trick. Distasteful chemicals advertised with brilliant colors.
34:48The joshua still has remnants of the ears that once warned it of approaching bats.
34:53But they are of no use against a sharp eye.
35:05Spit out, the moth may even escape with its life.
35:09But the bird has learned a lesson.
35:11Most predators learn quickly to associate colors with danger, resulting in a world of brilliantly patterned prey.
35:20He is a bird-deafone once in a while, and he's almost surrounded by a smear.
35:25He is a man who has shot for his firm in his eye.
35:30But of course, the loss of a female, a man who has fired him.
35:35He is a son-in-law.
35:37He is a man who is a man who is a man who is a man who's a man who is a man who is a man who is a man who is a man who is a man who is a man who is a man.
35:41In Oregon, lives the Tarracha newt.
35:59Orange pigment is a warning that it's more than distasteful.
36:06Each newt contains enough poison to kill 20,000 mice,
36:10or hundreds of people.
36:14In spring, they congregate to mate.
36:17A gathering of soft-bodied creatures should be a feast for predators.
36:25But local animals know the newts are deadly,
36:29and those that don't are warned off by a display of its orange belly.
36:35But why is the newt so poisonous,
36:44with enough toxin to kill thousands of crows,
36:47when enough to kill one would seem sufficient?
36:50Crows aren't the problem.
36:53Meet the newt's nemesis, the garter snake.
36:58Long ago, these snakes evolved a resistance to low doses of newt poison.
37:10Their prey fought back, producing more poison.
37:13Snakes countered with greater resistance.
37:16Predator and prey became caught in an escalating arms race.
37:21Every generation, the snakes get more resistant,
37:26and the newts more poisonous.
37:28The newt's nemesis is not poisonous.
37:54This arms race has now reached a ridiculous level.
37:57The newt spends much of its energy making poison,
38:00and the snake becomes paralyzed within moments of eating a newt.
38:05To survive the meal, the snake must wind down its metabolism
38:08while it neutralizes the poison.
38:11Vulnerable to predators, it must lie still for several hours.
38:17For the snake, it's not all bad news.
38:36After eating the newt, its tissues are saturated with toxin,
38:40so it becomes poisonous itself.
38:44The newt-eating race of garter snake is more brightly colored
38:48than its relatives elsewhere,
38:50possibly to advertise this secondhand poison.
38:53Poison is a great defense throughout the animal kingdom,
39:01even against master predators like bobcats.
39:05But poison is expensive to make,
39:07so the hognose snake has none and just pretends.
39:16Cats take the threat of venom seriously,
39:19so a posturing snake is approached with caution.
39:26There's meat on a snake, but one meal isn't worth dying for.
39:36The bobcat isn't fooled for long, and launches an attack.
39:40The cat's confidence grows, and the snake switches tactic,
40:00rolling onto its back and playing dead very convincingly.
40:05The hognose even reeks of death as a foul-smelling fluid oozes from its body.
40:19Many predators avoid corpses as a precaution against disease.
40:24The cat's interest wanes.
40:32But all the while, the snake is watching from the corner of its eye.
40:38Only when the cat has gone, does the snake seem to rise miraculously from the dead.
40:57It's an incredible display of deception.
41:00But where did this reptile learn its life-saving trick?
41:03The answer can be found in the underground nest of a hognose snake.
41:20As soon as the eggs hatch, the young snakes rush to leave the chamber.
41:24Such a concentration of yolk and young often attracts predators.
41:37The last to leave are the most at risk.
41:43Just hatched, the young snakes should be an easy target for a hungry rat.
41:47The rat moves in for the kill.
42:09But incredibly, the snake goes belly up and shows all the death-feigning trickery of the adult.
42:14This behavior is programmed into the genes.
42:19There was no time for the snake to learn this trick.
42:22Yet it can deceive a predator from the moment of hatching.
42:35Snakes don't always succeed.
42:37As they improve their performance, cats and rats improve their ability to see through the act.
42:45While the snake's display deters predators, other displays have evolved to attract them.
42:54As daylight fades in Puerto Rico, the waters of Mosquito Bay light up with eerie glows.
43:00Fish shoot through the water like fireworks, their outlines illuminating the night sea.
43:10These are the most glittering waters on Earth.
43:13Like the ghosts of fish, some have great length, others the flattened form of rays.
43:28Viewed with a special camera, the display is even more dazzling.
43:33But the source is still unclear.
43:38Add infrared light, invisible to most animals, and shapes begin to emerge from the gloom.
43:44Turn up the infrared, and lobsters can be clearly seen.
44:01They're antennae like sparklers.
44:04It's not the large animals that are glowing, but something in the water.
44:08Each spark comes from a single-celled organism called Noctiluca, that glows when disturbed.
44:17But why should they light up?
44:19Noctiluca are eaten by shrimp, but surely glowing will only attract them.
44:25They even continue to glow once inside the shrimp.
44:40Their light show doesn't go unnoticed by the shrimp's predators, cuttlefish.
44:45Noctiluca's display starts to make sense.
44:49The cuttlefish can't find shrimp in complete darkness.
44:52The shrimp is safe as long as it stays still.
44:56Even with pupils dilated, the cuttle sees nothing.
45:00But if the shrimp moves, Noctiluca sparkles and illuminates it.
45:05Now the cuttlefish can see the shrimp.
45:11The flashing Noctiluca, like a burglar alarm, gives away the shrimp's presence.
45:16By attracting cuttlefish with their flashing lights, Noctiluca protects itself against shrimp.
45:29The cuttlefish, by predating shrimp, is Noctiluca's ally.
45:34It's cat and mouse, and the shrimp can't win.
45:47If it stays still, it can't eat Noctiluca.
45:50And if it moves, a glittering trail attracts cuttlefish.
45:54For shrimp, hunting Noctiluca is a risky business.
45:57The cuttle gets a meal, but the real winner is Noctiluca.
46:09Every shrimp removed makes life safer for the tiny organism.
46:12Noctiluca's burglar alarm saves its life.
46:25But each tiny living spark is unaware of the defense strategy programmed into its genes.
46:30Coated into the genes of another creature is an even more elaborate display critical to its survival.
46:49In the streams of Missouri lives the Lampsilis mussel,
46:54a simple animal with an extraordinary life cycle.
46:56To reach adulthood, its young must spend part of their lives inside a fish, the largemouth bass.
47:08To get there, the mussels must make physical contact.
47:12A difficult task, as mussels don't swim.
47:17But the bass has a weakness.
47:20It's a voracious predator of small fish, particularly darters.
47:24Even the slightest wriggle of a darter's tail will attract bass.
47:35Believe it or not, the fish on the mussel is an imitation.
47:40A perfect replica that will lure bass within striking range.
47:43The mussel can somehow sense approaching fish, and wriggles its lure faster to entice them.
47:59If it gets the twitching just right, the remarkable likeness should do the rest.
48:04If it gets the twitching just right, the remarkable likeness should do the rest.
48:09On impact, the mussel squirts its young into the bass's mouth.
48:22These snap shut on the gills, like spring-loaded traps.
48:32Here they stay, drawing blood from the fish, until several weeks later they drop off as tiny, fully formed mussels.
48:40Also a favorite prey of the bass are these striped shiners, and some mussels mimic them.
48:55Considering mussels are blind, and have never seen a shiner, the likeness is incredible.
49:00The eyes, fins, and even the stripe look just right, yet the mussel knows nothing of its own appearance.
49:11These lures have evolved because bass more often attack mussels that look like fish.
49:17So fishy-looking mussels leave more descendants.
49:20After millions of years of blind evolution, this process of selection has turned mussel flesh into a lifelike lure.
49:37It takes a good imitation to fool a bass in clear water, and some of them are incredible.
49:44This starter mimic even has a mouth which gulps.
49:50This mussel is the same species, but its curious leopard print design may not find a taker, and its genes will go no further.
50:07This lure looks pretty good, but the bass is unconvinced, and turns it down.
50:13Mussel lures are constantly improving, but fish are getting ever better at recognizing fakes.
50:22It's another arms race, and it's still creating diversity in the streams of Missouri to this day.
50:28The battle between individuals to pass their genes onto the next generation has been shaping plants and animals since life began.
50:46In every corner of the planet, arms races are changing animal form and behavior.
51:05Understanding arms races provides a new dynamic view of life itself.
51:09Plants are at war with herbivores.
51:16Their defensive spines are countered by the elephant's toughened lips.
51:21The acacia grows upwards to escape its attackers, but its push for safety has been countered by the giraffe's long neck.
51:29The acacia and giraffe have shaped one another.
51:37The shape and behavior of all creatures are molded by other living things.
51:43Nothing evolves in isolation.
51:45Cheetahs created gazelles, just as gazelles created cheetahs.
51:53And even today, both are constantly changing.
51:58Evolution never stands still.
52:01The genes in each generation will be tested anew.
52:05It's a never-ending race for survival.
52:08The story of life has been, and always will be, a tale of genes battling to ensure their line triumphs.
52:27To learn more about what you've seen on this nature program, visit PBS.
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