"Most of us live here... [siren] ...the concrete jungle." "Suburbia." "But if you get out of town just beyond our backyards... it's wilder than you think." "This is the story of America's coasts." "Shores that stretch nearly pole to pole... born of fire and colliding continents... beaten by three great oceans." "Life here faces intense struggle and limitless opportunity." "Our coast is a stage for many of the greatest spectacles on Earth." "The richest water in the world." "The Peruvian coast of South America." "Sea lion paradise." "It's summer, birthing season." "This newborn is only a few days old." "[groaning]" "He's been born on one of the most crowded shores on Earth." "[birds squawking]" "But life on this beach is no holiday." "[growling]" "The pup's first week is critical." "He and mom must learn each other's smell and calls from among thousands of unruly sea lions." "[bellowing] [snorting]" "Rowdy males are on the rampage looking for mates." "A big male outweighs the pup 25 to one." "He's safe as long as mom's around." "But she hasn't eaten since he was born." "Like all new moms, she must hunt to keep up with his demand for milk." "He's alone for the first time." "[whines]" "[crying]" "All around him, other lone pups are being attacked." "Adolescent males too small to attract a mate take their frustrations out on the young." "[bellowing]" "The trick is to go unnoticed." "But the pup can't help but call for mom." "[groans]" "And that attracts attention." "[snorting] [crying]" "This pup's got guts." "But he needs his mother if he's to survive." "She's been out close to a week and is finally headed home." "But now she must find her son from among thousands of sea lions." "[bellowing]" "[whines]" "The pup survives." "Mating season is not over yet." "But he's through the hardest week." "And soon he'll learn to hunt for himself." "Life on America's shores thrives because there's an abundance of food." "And currents are the key." "Cold currents carry food up the Pacific Coast, towards Central America..." "A coastline forged by volcanoes." "When currents collide with volcanic islands, nutrients from the deep are driven to the surface." "Fuel for one of the most spectacular food chains on Earth." "Rich water draws in millions of sardines." "They are the real feast." "Nearly all of this school will die." "Sea lions strike first." "Then sharks appear." "The sardines ball together." "Alone, they're easy targets." "Predators use this to their advantage." "Finally, the real stars arrive." "Marlin travel more than 1 ,000 miles at speeds up to 50 miles an hour." "They're usually loners, but feeding events like this bring them together in extraordinary numbers." "They use their sword not to skewer the sardines, but to knock them senseless." "They feast along this coast for just a few weeks, until the surviving sardines move on." "Further north, the same forces that create Central America's volcanoes also tore a deep chasm from the mainland... the Sea of Cortez." "The Baja Peninsula shelters this deep abyss from the mighty Pacific." "When the sun goes down, a monster emerges from the deep." "El diablo rojo-the red devil." "Tonight, an army of Humboldt squid rises from the deep." "Up to 1 ,000 strong, each one can grow as long as a person and weigh up to 1 00 pounds." "Surprisingly intelligent, they communicate by flashing messages with their skin." "Seen with eyes the size of billiard balls." "1 0 limbs lined with hooks and suction cups drag victims to a raptor-like beak." "These squid show no mercy." "Even for their own." "They're cannibals." "A defensive squirt of ink is too little, too late." "Daybreak calms their frenzy, and they retreat back into the deep." "Sunrise reveals Baja's true grandeur." "Colliding currents around the peninsula create an endless buffet of food." "A refueling station for migrating behemoths." "Millions of tiny krill attract the largest animal on Earth." "The blue whale." "She'll suck up to eight tons of krill in a single day." "Whale sharks, the largest fish in the ocean, travel thousands of miles." "They're here for the plankton." "Gray whales come to these protected shores to mate and give birth." "[whales drumming]" "Baja's coastline provides rare harbor for the ocean's giants." "It's also the meeting place for one of the Pacific's most mysterious travelers." "Mobula rays are often seen off Baja." "But this year is one for the record books." "Exactly why they're here is not known." "But tens of thousands of rays have come together in an epic gathering." "Quite possibly the largest school ever filmed." "With wings seven feet from tip to tip, why not fly?" "And then they vanish as quickly as they appeared." "As summer approaches, many of Baja's giants migrate north, through the Gulf of Alaska." "These icy waters are feeding grounds for countless ocean wanderers." "[dolphin squeaking]" "But their fates can also affect the fortunes of those on land." "Grizzly bears are not afraid of getting wet." "A hungry grizzly smells an unexpected opportunity." "Millions of calories have washed ashore." "A beached humpback whale." "Grizzlies are usually solitary." "But the smell draws them together from miles away." "They're not used to sharing." "[growling]" "Latecomers are especially unwelcome." "[growling]" "He settles for the short end of the whale, a safe distance from the others." "There's not much to eat on the tail." "But all he has to do is wait." "Soon the other bears eat their fill and then some." "[panting]" "It's like after a Thanksgiving feast." "With everyone else in a food coma, the hungry male helps himself to stress-free seconds." "This unexpected windfall helps sustain these grizzlies through the long, cold winter." "North America's Pacific shores stretch from the Alaskan wilderness to the California coast." "One of the most familiar and iconic coastlines on the planet." "But just offshore, there is an alien world." "A forest of 1 50-foot kelp rises from the ocean floor." "At the bottom, a dormant army lies in wait." "A massive swarm prepares to invade the coast." "They're no larger than a grain of rice." "Polyps." "No one knows exactly why they wait." "It can take years." "But this summer, millions of polyps all change at once." "Segments form." "The top one twitches." "A jellyfish is born." "ln a few months, the sea nettle jellyfish grows several hundred times in size." "It trails 1 6 feet of stinging tentacles." "But despite these weapons, it has a nemesis living in the kelp forest." "Shrimp-like carnivores not much bigger than a flea." "Amphipods." "An infestation can eat its way through a sea nettle in days." "But help is on the way." "A second hitchhiker targets the first." "For the crab, it's as easy as plucking fruit from a tree." "For the jelly, it's like having armed guards." "Even with this security, jellyfish live less than a year." "By next summer, they'll be gone." "And it could be years before they bloom in these numbers again." "The powerful Pacific batters the entire west coast of the Americas." "Across the continents to the east, the world's other great ocean fuels an entirely different world." "Several hundred miles from Antarctica, the Falkland lslands sit at the southern edge of the Atlantic Ocean." "One of the most isolated places on Earth." "Swells build to 30 feet." "The water feels freezing cold." "Gale force winds are common." "A paradise for penguins." "It's January, summer in the Falklands, and a two-year-old gentoo has one thing on his mind..." "Chasing tail." "But he's young, and he's never done this before." "He could be in for a dangerous ride." "This young penguin must follow some simple steps to score a mate." "Step one..." "Find a girl." "[honking] [squawking]" "Step two..." "Make sure she's single." "Step three..." "Give her a nice rock." "But what she really wants is a home." "So they build a nest." "[cooing]" "Construction approved." "It's no castle, but it does the job." "Honeymoon over, it's time to go fishing." "When gentoos hunt, they're all in." "At sea, they're in their element." "But they're not alone." "A southern sea lion hunts." "For penguins, there's safety in numbers." "For all but one." "Parents back at the nest wait for their partners' return." "Both parents must hunt to keep the family fed." "Single-parent chicks stand little chance of survival." "This guy was lucky today." "A pair can raise over a dozen chicks in their lifetime here in the frigid waters of the southern Atlantic." "The shores of the Americas wind more than 1 00,000 miles." "From the extreme south, to the other end of the world... the Arctic Ocean." "Polar bears in the Canadian Arctic hunt seals on these waters." "But only when they're frozen." "This mother polar bear hasn't eaten much all summer." "Unless the ocean freezes soon, she'll run out of milk, and her twin cubs will starve." "But the freeze is late." "No one's hunting on this sea anytime soon." "They must wait on shore." "But land can be even more dangerous." "[growling]" "These irritable males are also desperate for the ice to freeze." "To get in shape while they wait, they fight." "[growling]" "It's any mom's worst nightmare." "At over 1 ,000 pounds each, a big male could easily kill the cubs." "Stuck between an unfrozen sea and violent males, a mother polar bear is in a desperate spot." "A hungry male bear would gladly eat a cub." "But this mom can defend her twins to the death." "[snorting, grumbling]" "As December approaches, the freeze finally comes." "Soon the ice will be six feet thick." "At last, they can get out onto the frozen sea." "America's coastline reaches from the frozen water of the Arctic to some of the warmest water in the world." "The tropical Atlantic and the Caribbean Sea." "A rich, shallow world with hundreds of islands and miles of coral reef." "Crowded with life." "One animal truly thrives in paradise." "Dolphins." "[squeaking]" "And nowhere more than here..." "Brazil's Fernando de Noronha National Marine Park." "Home to one of the largest resident groups of dolphins in the world." "This young female has recently come of age." "She's one of an extended family, numbering in the thousands..." "Known as spinners... for good reason." "Each splash is thought to mean something different." "Anything from "let's move,"" "to "danger,"" "to "let's get it on."" "This communication is key to their social lives as is sex." "Spinners' penises are pencil-thin and only a few inches long, max." "Lucky for female spinners, it's not about size, but frequency." "She could mate with several different males today alone." "Mothers keep a strong bond with their calves, but don't know who the father is." "Because males don't know which calves are theirs, they protect them all." "It's an unconventional family." "But it works for them." "Like every animal that lives along our shores, dolphins have learned to make the most of these waters." "The coastline of the Americas is the most diverse and extreme on Earth." "And it offers spectacular riches for those who know where and when to find them."