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We live on an ever-moving planet.
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(dramatic music)
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It's the driver that brings seasonal change.
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And as landscapes are altered,
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wildlife must march to its rhythm,
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performing endless journeys.
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As if by magic, they follow a map, built into their DNA,
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driven by instinct,
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and the wisdom of the thousands of generations
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who have gone before.
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Migration is a phenomenon that wows us
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as animals show incredible feats of endurance.
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Some run, some fly,
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but most swim,
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performing some of the longest journeys on earth,
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facing endless hurdles.
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But for marine migrators, nothing can turn the tide.
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These creatures were born ready for the big swim.
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(gentle music)
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Giants are on the move.
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Gray whales chose the warm waters
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off the Pacific coast of Mexico to breed.
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In the clear shallows, it's easier to keep their calves safe
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from predators like sharks.
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But migration is built into the ancient DNA
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of these animals.
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They're driven to keep on the move.
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But as they leave coastal lagoons and enter open ocean
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to travel north, they face danger head-on,
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killer whales.
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Giant members of the dolphin family,
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the sleek predators are sometimes known
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as the wolves of the sea.
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(whales crashing)
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Because like wolves, they hunt in packs
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and perform coordinated attacks.
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They're capable of killing even the biggest of whales,
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but the adult grays are known to put up quite a fight.
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(dramatic music)
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The killers are after the baby.
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They must drive a wedge between the frightened calf
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and its defensive mother.
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The female will do all she can to stand her ground.
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But she's outnumbered.
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The killer whales chase until the calf is tired.
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They nip and push it under water,
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preventing it from catching its breath.
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Despite the mother's efforts, it's too late.
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Undertaking migration is a huge risk.
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There are many calves that won't make it.
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But by hugging the coastline, sticking to shallow waters,
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some mothers will successfully escort their calves
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across an ocean.
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Gray whales perform some of the biggest journeys of all,
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a round trip of 20,000 kilometers.
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This is why.
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During summer, the northern extremes of the planet
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get much longer hours of sunlight than the tropics.
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More light means more plant growth,
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or in the sea, algae.
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It feeds the base of the food chain,
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making the cold waters of the North Pacific
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some of the most productive on the planet.
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(soaring music)
(waves crashing)
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Gray whales can gain several tons
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in just a few short months,
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thanks to the shellfish they can sift from the seabed.
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But as the autumn creeps in,
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the days get shorter and the water colder.
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This is no place to raise young.
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So the whales quit binging and head south again.
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During its lifetime, a gray whale covers enough ground
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to get to the moon, come home,
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and go back to the moon again.
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These are typical drivers
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to move from one habitat to another,
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to find favorable conditions to raise young
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or to exploit a major food source.
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(dramatic music)
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All across the ocean, giants are on the move.
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Marine life undertake some of the biggest migrations
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on earth.
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Driven by currents, changing with the seasons,
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bringing in or washing out great riches,
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motivated by the need to be in the right place
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at the right time.
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The biggest animal mass on the move isn't the giants.
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It's the little guys by sheer number.
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Herring move between feeding and spawning grounds.
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Some populations also make a winter stop off.
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In the deep fields of Norway,
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the fish gather in unimaginable numbers
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to sit out the worst of winter,
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but as they pour into the submarine valleys,
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predators follow,
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humpback whales.
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These giants undertake the longest known migrations
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of any mammal, 8,000 kilometers each way.
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Some reroute to cash in on the herring,
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and they are being tailed.
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Killer whales,
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but these ones are different.
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Unlike the whale eaters of the Pacific,
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the whales here prefer fish.
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They are joining the humpbacks for a feast.
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The orcas work together to concentrate the fish,
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scaring them with squeals.
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(whales squealing)
(dramatic music)
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And then release their weapons,
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powerful blows from their tails.
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The shock waves from the strikes are so forceful
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that they literally stun the fish.
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The killer whales can hoover them up one-by-one.
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(seagulls squawking)
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The humpbacks are less delicate.
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When they get to a tightly packed ball of fish,
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they simply open their mouths to engulf the lot.
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Pleats in their throats expand
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allowing them to take in more than 20,000 liters of water,
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the amount of a fair-sized backyard swimming pool.
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Then the throat contracts forcing the water out,
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but trapping the fish behind their baleen.
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One whale can eat more than two tons of herring a day.
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The humpbacks and the surviving herring
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will resume their migration once the weather improves,
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moving to rich feeding grounds to the north.
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Food is one of the primary motivators of migration.
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Seasonal abundance is worth the epic struggle.
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For big bodies, it takes hard work to gather enough food,
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especially if you eat the smallest creatures in the sea.
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Basking sharks are the second biggest fish on earth.
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Longer and heavier than a minibus, they need plenty of food.
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The sharks spend winter 1,000 meters or more
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in the depths of the ocean.
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But in summertime when strong light fuels algal growth,
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they migrate to the shallows,
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for feeding on the algae are plankton, lots of plankton.
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And that's what the giant fish sieve from the seas
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simply swimming open mouthed through the shoals
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and sieving the tiny creatures
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with net-like structures in their gills.
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But not all migrations are driven by food.
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The waters around the Galapagos
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undergo dramatic changes through the year.
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They have two key seasons.
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For half the year, they're bathed by the warm waters
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of the Panama current and trade winds
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that create the wet season on land.
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But this is a hard time for marine life.
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The tropical seas are not very productive.
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But the dry season is brought on by a shift in currents.
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The Humboldt Current swarms the Galapagos with cold water
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brought up from the Antarctic.
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Because the Antarctic gets long sunlight hours,
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it's highly productive.
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The water flowing from it is packed with nutrients.
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Now there is a time of abundance for the fish.
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Many oceanic species visit.
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(gentle music)
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But not all of them are after food.
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Hammerhead sharks are ocean wanderers,
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but during their travels, they accumulate parasites
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and other blemishes on their skin.
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To fix the problem, they hire cleaners.
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A little head nod over the reef
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(playful music)
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is a signal that it's here for spa treatment, not dining.
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And the fish willingly oblige.
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The pests and dead skin are a feast for the fish.
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And after their stop at the health spa,
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the spruced-up sharks can continue their journeys.
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Hammerheads travel for food, cleaning services,
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and to find a mate.
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The Galapagos is one of the few places
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where huge aggregations occur.
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They like to be discreet when it comes to sex.
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No one has ever seen it,
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but it's likely the coupling happens
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during their big social events.
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Many of the females have bite wounds on their fins,
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the love bites of males holding on during mating,
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testimony to their nuptial encounters.
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The Galapagos, like many other archipelagos
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and tropical coasts, attract lots of animals
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looking to enrich their sex lives.
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Green sea turtles, just one of seven species
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that undertake similar journeys.
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Turtles have long, slow lives,
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but they don't shy away from some serious swimming.
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(upbeat music)
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Because they're reptiles,
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they hatch from eggs laid on beaches.
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For five to seven years, they make long migrations
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around the Eastern tropical Pacific
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living an oceanic lifestyle.
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Then they head to coastal waters.
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But the journey's don't stop as they move
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between feeding grounds.
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Only once around 30 years old do they think about sex.
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After hatching, male turtles never return to land,
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but they will make their way to breeding sites
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where they hang out looking for females on the reef.
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The hopeful males turn up every year,
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(gentle playful music)
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but the females only come to breed every two to five years.
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So scrums are common as males try to lay claim
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to the receptive females.
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During coupling, the male does his best to hold on.
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(gentle music)
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Other males will try to muscle in.
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But one-by-one, they give up
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and head back to the reef to continue their search.
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Once mated, the female will set off on yet another journey
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back towards the beach where her own life began.
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Not all swimming marathons are marine.
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Across the world, streams and rivers
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host epic fish Olympics.
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(upbeat music)
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More than half of all fresh water fish species migrate
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between feeding, breeding, or wintering grounds.
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(slow gentle music)
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In temperate regions, winters can be cruel.
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Ice-locked rivers and lakes can make it hard to move around.
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But as soon as winter's power starts to ebb,
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fish get busy.
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Pike are one of the first.
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It's the perfect time for their high-energy journey.
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(upbeat music)
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Snow is melting all over the landscape,
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gushing into waterways, churning oxygen into them.
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The powerful fish exploit the oxygen
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in their battle against the currents.
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The epic struggle, just so that they can deposit their eggs
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in the perfect spot.
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The meltwater is a valuable resource, but it's shallow.
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(dramatic music)
(fish splashing)
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Like all migrations, their struggle is an essay
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in determination and endurance.
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The pike run the risk of grounding themselves on the rocks.
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And that's not the only danger.
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(bird squawking)
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Migrating cranes and other birds drop in
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to take advantage of any casualties.
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(birds squawking)
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Eventually, most will make it
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and spawn before wriggling back
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to their summer feeding grounds.
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The eggs develop,
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and in only a few weeks, hatch,
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and the tiny larvae begin to patrol,
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already feeling their predatory instincts.
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These baby pike have never migrated,
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but they are born with the instinct.
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And when they mature in a few years,
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they too will join the epic struggle upstream.
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For most fish, the process of baby-making
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is simply to squirt out eggs and sperm
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and let nature do the rest.
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For other swimmers, it's more of an uphill struggle.
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An ocean giant is nearing the end of a great journey.
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Leatherback turtles are the biggest of their kind,
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little changed since the time of the dinosaurs,
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but their vast size doesn't hold them back.
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Over the year, this female has traveled
265
00:24:27,320 --> 00:24:29,530
more than 6,000 kilometers
266
00:24:29,530 --> 00:24:31,880
from feeding grounds along the coast of Canada.
267
00:24:36,430 --> 00:24:37,613
And this is why,
268
00:24:39,380 --> 00:24:42,930
the long sandy beaches of an island of Western Africa
269
00:24:44,360 --> 00:24:46,953
where her own life began many decades ago.
270
00:24:49,030 --> 00:24:51,883
Her streamlined body is the perfect hydrofoil.
271
00:24:54,390 --> 00:24:57,660
Powered by huge flippers, she can fly through the ocean
272
00:24:57,660 --> 00:24:59,723
at more than 30 kilometers per hour.
273
00:25:03,230 --> 00:25:08,203
But now on the beach, every stride is a monumental struggle.
274
00:25:10,700 --> 00:25:13,783
She must drag her one-ton bulk above the tide line,
275
00:25:15,780 --> 00:25:17,573
searching for the perfect spot,
276
00:25:19,090 --> 00:25:21,950
not so high up the beach that it dries out,
277
00:25:21,950 --> 00:25:25,623
but not low enough for it to get waterlogged by a high tide,
278
00:25:26,830 --> 00:25:28,860
and with just enough sun exposure
279
00:25:28,860 --> 00:25:30,763
to create the perfect temperature.
280
00:25:32,390 --> 00:25:36,473
She's aiming for a nest that holds at 27.5 degrees.
281
00:25:38,450 --> 00:25:40,030
If she gets it right,
282
00:25:40,030 --> 00:25:42,713
she'll produce equal numbers of boys and girls.
283
00:25:44,360 --> 00:25:47,710
If the nest is warmer, more will be female,
284
00:25:47,710 --> 00:25:50,513
and cooler will result in more males.
285
00:25:53,380 --> 00:25:56,270
She will make this gargantuan journey up the beach
286
00:25:56,270 --> 00:25:58,263
several times during the season,
287
00:26:02,890 --> 00:26:05,930
and each time deposit around 100 rubbery,
288
00:26:05,930 --> 00:26:07,673
ping pong ball-sized eggs.
289
00:26:11,274 --> 00:26:14,441
(inspirational music)
290
00:26:17,130 --> 00:26:19,040
She gently covers the nest site
291
00:26:43,540 --> 00:26:46,083
and begins a hard exit back to the sea.
292
00:26:48,810 --> 00:26:50,663
This is the end of her motherhood.
293
00:26:59,420 --> 00:27:02,673
In two months time, the eggs will be ready to hatch,
294
00:27:03,910 --> 00:27:08,660
but they will do so alone, again driven by instinct
295
00:27:08,660 --> 00:27:10,583
to take up their lifetime of journeys.
296
00:27:35,025 --> 00:27:37,692
(waves lapping)
297
00:27:43,010 --> 00:27:46,570
Migrations have long captured the human imagination,
298
00:27:46,570 --> 00:27:49,173
but few more so than the journey of salmon.
299
00:28:00,910 --> 00:28:03,530
These mighty fish don't just move themselves
300
00:28:03,530 --> 00:28:05,510
from one area to another,
301
00:28:05,510 --> 00:28:10,250
but from fresh water to the sea and then back again,
302
00:28:10,250 --> 00:28:14,363
forcing transformations that literally destroy their bodies.
303
00:28:17,290 --> 00:28:19,813
It's the unstoppable instinct of migration.
304
00:28:25,696 --> 00:28:28,446
(birds chirping)
305
00:28:34,120 --> 00:28:36,320
Salmon begin life hatching from eggs
306
00:28:36,320 --> 00:28:39,053
in small freshwater streams far inland.
307
00:28:42,440 --> 00:28:45,143
Several very different life phases lie ahead.
308
00:28:48,810 --> 00:28:51,577
Newly-hatched salmon are known as alevin.
309
00:28:53,060 --> 00:28:55,410
Tiny tails push along the big yolk sacs
310
00:28:55,410 --> 00:28:58,133
that nourish them while their bodies grow.
311
00:29:11,660 --> 00:29:14,010
Gradually, the delicate translucent forms
312
00:29:14,010 --> 00:29:15,563
start to look more fish-like.
313
00:29:20,600 --> 00:29:24,900
These are par, small, stripey, freshwater fish
314
00:29:24,900 --> 00:29:26,730
that can forage for little organisms
315
00:29:26,730 --> 00:29:28,653
in the streams where they hatched.
316
00:29:31,960 --> 00:29:35,680
For six months or more, sometimes even a few years,
317
00:29:35,680 --> 00:29:37,513
their lives will remain constant.
318
00:29:39,700 --> 00:29:42,019
But then a cue from deep within
319
00:29:42,019 --> 00:29:45,225
(upbeat music)
320
00:29:45,225 --> 00:29:47,353
tells the fish to move downstream.
321
00:29:55,970 --> 00:29:58,850
Their bodies are changing inside as well as out
322
00:29:58,850 --> 00:30:01,730
to cope with the transition from clean, fresh water,
323
00:30:01,730 --> 00:30:03,380
to the high salt content
324
00:30:03,380 --> 00:30:05,653
and lower temperatures of the open ocean.
325
00:30:09,950 --> 00:30:13,583
After a few years, up to five depending on the species,
326
00:30:15,200 --> 00:30:18,623
adult salmon feel an unignorable urge to breed,
327
00:30:21,381 --> 00:30:22,700
and they begin their titanic journeys
328
00:30:22,700 --> 00:30:24,100
to the place of their birth.
329
00:30:28,660 --> 00:30:30,820
The fish follow the earth's magnetic fields
330
00:30:30,820 --> 00:30:32,870
to aim for the coast,
331
00:30:32,870 --> 00:30:34,600
then recognize the chemical smell
332
00:30:34,600 --> 00:30:36,470
of the river they were born in,
333
00:30:36,470 --> 00:30:39,233
using that path to guide them inland.
334
00:30:45,196 --> 00:30:50,196
(birds chirping)
(water flowing)
335
00:30:51,720 --> 00:30:53,223
As they enter the shallows,
336
00:30:54,570 --> 00:30:56,363
predators gather to greet them.
337
00:30:59,450 --> 00:31:01,933
These bears have been waiting for several days,
338
00:31:05,090 --> 00:31:08,480
knowing that any moment the flood gates will open
339
00:31:08,480 --> 00:31:10,973
with fleets of salmon charging into the rivers.
340
00:31:21,488 --> 00:31:25,860
For bears, the salmon run is a vital resource.
341
00:31:25,860 --> 00:31:28,890
It's no surprise that they camp out waiting for the fish.
342
00:31:51,221 --> 00:31:53,971
(dramatic music)
343
00:32:42,850 --> 00:32:45,260
Bears only have a narrow window before winter
344
00:32:45,260 --> 00:32:46,360
when they can bulk up.
345
00:32:50,870 --> 00:32:53,970
They need huge amounts of fat stored in their bodies
346
00:32:53,970 --> 00:32:56,320
if they are to survive their long winter sleep.
347
00:33:01,410 --> 00:33:03,580
Some populations are totally dependent
348
00:33:03,580 --> 00:33:04,843
on the salmon migration.
349
00:33:06,090 --> 00:33:08,690
It comes at just the right time for them to top off.
350
00:33:10,620 --> 00:33:14,483
It literally makes the difference between life and death,
351
00:33:17,930 --> 00:33:19,503
something worth fighting for.
352
00:33:23,020 --> 00:33:25,310
But as the rivers fill with fish,
353
00:33:25,310 --> 00:33:29,053
the normally solitary bears develop a temporary tolerance.
354
00:33:31,710 --> 00:33:33,360
There's enough fish for everyone.
355
00:33:34,215 --> 00:33:36,882
(playful music)
356
00:34:11,940 --> 00:34:14,493
Gulls, crows, and eagles gather.
357
00:34:18,600 --> 00:34:20,040
There are so many salmon
358
00:34:20,040 --> 00:34:22,400
that the bears simply nibble off the best bits
359
00:34:22,400 --> 00:34:23,753
and move on to the next.
360
00:34:25,130 --> 00:34:27,430
There are plenty of scraps for watchful birds.
361
00:34:52,840 --> 00:34:54,580
A big bear might consume
362
00:34:54,580 --> 00:34:57,793
2 or 3,000 kilos of fish per season.
363
00:35:11,410 --> 00:35:13,810
For the fish that dodge bear claws,
364
00:35:13,810 --> 00:35:15,553
the struggles have barely begun.
365
00:35:16,534 --> 00:35:21,534
(water gurgling)
(foreboding music)
366
00:35:31,360 --> 00:35:33,623
Many species spawn at elevation,
367
00:35:34,500 --> 00:35:37,093
so not only must they battle against the current,
368
00:35:40,220 --> 00:35:42,113
but also scale mountains.
369
00:35:44,350 --> 00:35:48,143
Athletes of the fish world, salmon can climb waterfalls.
370
00:36:08,175 --> 00:36:09,320
Triggered by the change in chemistry
371
00:36:09,320 --> 00:36:11,460
and lower salt level of the rivers,
372
00:36:11,460 --> 00:36:13,633
they change the way they use their bodies.
373
00:36:19,100 --> 00:36:20,430
Instead of the muscle groups
374
00:36:20,430 --> 00:36:23,660
that normally power fast, straight swimming,
375
00:36:23,660 --> 00:36:26,423
they switch to ones that power bursts of speed.
376
00:36:29,040 --> 00:36:32,940
Bending in a tight S-shape, flipping from side to side,
377
00:36:32,940 --> 00:36:35,050
they create thrust against the water
378
00:36:35,050 --> 00:36:36,973
and launch themselves into the air.
379
00:36:41,260 --> 00:36:44,183
Skyrocketing, they can clear three meters.
380
00:36:53,580 --> 00:36:56,130
Some battle hundreds of kilometers inland,
381
00:36:56,130 --> 00:36:58,063
through strong currents and rapids.
382
00:37:08,585 --> 00:37:11,413
A few populations swim 1,400 kilometers
383
00:37:12,260 --> 00:37:14,020
into mountain ranges,
384
00:37:14,020 --> 00:37:17,303
climbing more than 2,000 meters in elevation,
385
00:37:19,060 --> 00:37:21,340
and all the while their bodies
386
00:37:21,340 --> 00:37:23,373
are undergoing massive changes.
387
00:37:25,320 --> 00:37:28,020
Some species radically alter their appearance
388
00:37:28,020 --> 00:37:29,520
ready for the breeding season.
389
00:37:31,870 --> 00:37:33,913
None more so than the sockeye.
390
00:37:36,610 --> 00:37:39,170
Normally sleek and silver,
391
00:37:39,170 --> 00:37:41,893
they now display fiery red breeding colors.
392
00:37:43,980 --> 00:37:47,500
The males grow massively enlarged shoulder humps,
393
00:37:47,500 --> 00:37:50,400
so they look pumped up to impress the girls
394
00:37:50,400 --> 00:37:51,883
and intimidate rivals.
395
00:37:54,110 --> 00:37:57,090
Exhausted, the fish that have dodged death
396
00:37:57,090 --> 00:37:59,063
finally reached the spawning streams.
397
00:38:03,950 --> 00:38:05,520
While they've been traveling,
398
00:38:05,520 --> 00:38:08,450
the females have been developing eggs inside them,
399
00:38:08,450 --> 00:38:12,370
and they are now ready to deliver their precious cargo,
400
00:38:12,370 --> 00:38:14,168
known as roe.
401
00:38:14,168 --> 00:38:16,751
(gentle music)
402
00:38:20,400 --> 00:38:22,940
They select only fast-flowing streams
403
00:38:22,940 --> 00:38:25,410
where the current will flow over the eggs,
404
00:38:25,410 --> 00:38:28,213
keeping them clean and well oxygenated.
405
00:38:32,590 --> 00:38:34,430
With a few sweeps of the tail,
406
00:38:34,430 --> 00:38:37,000
a female can scoop out a gravelly nest
407
00:38:37,000 --> 00:38:38,683
into which she deposits the roe.
408
00:38:47,600 --> 00:38:50,223
As she's laying, eager males gather.
409
00:38:54,700 --> 00:38:56,570
There's stiff competition,
410
00:38:56,570 --> 00:38:58,970
but the males have also been developing weapons.
411
00:39:02,830 --> 00:39:05,623
Their jaws have become elongated and arched,
412
00:39:07,440 --> 00:39:09,523
and packed full of canine-like teeth.
413
00:39:11,440 --> 00:39:15,150
Like nightmarish crocodiles, they can nip at rivals
414
00:39:28,110 --> 00:39:30,610
They try to fight their way to the top of the line
415
00:39:30,610 --> 00:39:32,613
to be alongside the spawning female.
416
00:39:37,940 --> 00:39:39,710
The victim will mark his triumph
417
00:39:39,710 --> 00:39:42,193
by squirting sperm over the roe-filled nest.
418
00:39:49,680 --> 00:39:51,720
With fertilization complete,
419
00:39:51,720 --> 00:39:54,283
the female gives another few sweeps of her tail,
420
00:39:56,100 --> 00:39:58,573
stirring up gravel to gently cover the eggs.
421
00:40:03,830 --> 00:40:07,620
Then finally, their unimaginably demanding mission
422
00:40:07,620 --> 00:40:08,543
is complete.
423
00:40:11,774 --> 00:40:14,160
The energy required to fight inland,
424
00:40:14,160 --> 00:40:16,650
the massive impact of remodeling their bodies
425
00:40:16,650 --> 00:40:20,910
to cope with fresh water and to arm them to breed,
426
00:40:20,910 --> 00:40:24,223
and the art of spawning have all taken their toll.
427
00:40:25,450 --> 00:40:28,850
They also haven't eaten for months.
428
00:40:28,850 --> 00:40:32,160
Their withered bodies have given all they have to give
429
00:40:32,160 --> 00:40:34,223
and literally fall apart.
430
00:40:37,760 --> 00:40:40,820
After one of the most epic journeys on earth,
431
00:40:40,820 --> 00:40:43,433
they find peace back in the rivers of their birth.
432
00:40:46,650 --> 00:40:48,150
But the salmon's death
433
00:40:48,150 --> 00:40:50,423
is perhaps their greatest gift of all.
434
00:40:51,430 --> 00:40:54,640
In their struggles, the fish have carried nutrients
435
00:40:54,640 --> 00:40:56,293
from the sea in their bodies.
436
00:40:57,350 --> 00:41:00,933
As they rot, the nutrients are released into the water,
437
00:41:03,010 --> 00:41:06,033
providing essential minerals to the surrounding landscape.
438
00:41:08,800 --> 00:41:10,730
This ensures that their offspring
439
00:41:10,730 --> 00:41:13,733
will grow up in rich waters full of food,
440
00:41:14,610 --> 00:41:16,400
but way beyond that,
441
00:41:16,400 --> 00:41:19,630
they're literally fertilizing an entire forest
442
00:41:19,630 --> 00:41:21,230
and everything that lives in it.
443
00:41:23,480 --> 00:41:27,043
Without salmon, the forest would be a poorer place,
444
00:41:28,744 --> 00:41:31,623
all thanks to the driving force of migration.
445
00:41:34,960 --> 00:41:37,830
Of course, bears and birds are not the only predators
446
00:41:37,830 --> 00:41:39,463
the migrating salmon face.
447
00:41:41,400 --> 00:41:43,210
Fishermen also descend on the rivers
448
00:41:43,210 --> 00:41:45,660
for the sport of luring salmon to their bait
449
00:41:45,660 --> 00:41:47,423
and fighting the powerful fish.
450
00:41:55,850 --> 00:41:58,070
Fortunately in most places,
451
00:41:58,070 --> 00:42:00,190
the harvest doesn't have a massive impact
452
00:42:00,190 --> 00:42:01,393
on the salmon stocks.
453
00:42:03,230 --> 00:42:05,213
But many human activities do.
454
00:42:07,250 --> 00:42:11,393
By its very nature, migration puts animals in danger.
455
00:42:13,800 --> 00:42:16,860
In some places, fishing, development,
456
00:42:16,860 --> 00:42:19,540
and other human activities may be controlled
457
00:42:19,540 --> 00:42:21,103
to help protect wildlife,
458
00:42:25,840 --> 00:42:28,963
but migrators don't recognize international boundaries.
459
00:42:31,770 --> 00:42:34,230
They might be protected in one area,
460
00:42:34,230 --> 00:42:36,163
but then exploited in the next.
461
00:42:38,750 --> 00:42:40,450
Their wanderings make it very hard
462
00:42:40,450 --> 00:42:42,163
to strategize their protection,
463
00:42:44,350 --> 00:42:47,800
and it's especially tough for marine migrators.
464
00:42:47,800 --> 00:42:49,930
The swimming animals spend most of their lives
465
00:42:49,930 --> 00:42:52,023
underwater and out of sight.
466
00:42:53,820 --> 00:42:56,223
It's hard to see what's going on in their lives.
467
00:42:59,900 --> 00:43:03,710
Data is lacking, but already clearly shows
468
00:43:03,710 --> 00:43:06,313
that the majority of species are in decline.
469
00:43:09,730 --> 00:43:14,020
These international travelers really do belong to everybody
470
00:43:14,020 --> 00:43:16,393
and need everyone's help to survive.
471
00:43:18,133 --> 00:43:21,660
(whales squealing)
472
00:43:21,660 --> 00:43:24,110
And there is another more recent challenge
473
00:43:24,110 --> 00:43:25,310
that humans have caused.
474
00:43:26,870 --> 00:43:30,260
Our activities have altered the gases in the atmosphere
475
00:43:31,350 --> 00:43:33,543
and change the chemistries of the seas.
476
00:43:35,480 --> 00:43:38,323
Climate change affects the seasons all over the world.
477
00:43:40,340 --> 00:43:43,600
Migrating animals might arrive too early or too late
478
00:43:43,600 --> 00:43:45,423
to find the conditions they need.
479
00:43:47,300 --> 00:43:50,830
Research reveals that 80% of marine migrators
480
00:43:50,830 --> 00:43:53,530
have already changed the routes and timings
481
00:43:53,530 --> 00:43:55,480
that they have been following for eons.
482
00:44:00,360 --> 00:44:01,610
Some have altered their course
483
00:44:01,610 --> 00:44:03,853
by as much as 1,000 kilometers.
484
00:44:08,405 --> 00:44:11,072
Warmer seas are less productive.
485
00:44:12,440 --> 00:44:15,830
Some species seem able to adapt quickly to the changes,
486
00:44:15,830 --> 00:44:17,480
but are showing massive die-offs
487
00:44:17,480 --> 00:44:20,033
due to starvation and breeding failures.
488
00:44:23,700 --> 00:44:25,970
More than ever, we need to manage
489
00:44:25,970 --> 00:44:28,203
and minimize our footprint on the planet,
490
00:44:31,250 --> 00:44:35,683
for the sake of migrators as well as ourselves.
491
00:44:40,410 --> 00:44:41,613
But there is hope.
492
00:44:42,720 --> 00:44:46,823
Despite the odds, life shows tremendous resilience.
493
00:44:53,840 --> 00:44:56,740
On that quiet beach of Western Africa,
494
00:44:56,740 --> 00:44:59,103
the sand seems to spring to life.
495
00:45:08,730 --> 00:45:10,720
Both green and leatherback hatchlings
496
00:45:10,720 --> 00:45:12,620
are digging their way from the ground.
497
00:45:17,430 --> 00:45:20,250
It's already been an arduous task.
498
00:45:20,250 --> 00:45:21,670
They've had to tunnel through the weight
499
00:45:21,670 --> 00:45:25,053
of more than 50 centimeters of sand that covered their nest.
500
00:45:27,530 --> 00:45:29,853
But the challenge has barely begun.
501
00:45:32,420 --> 00:45:33,730
Though you could fit a handful
502
00:45:33,730 --> 00:45:36,570
of these tiny turtle hatchlings in your pocket,
503
00:45:36,570 --> 00:45:38,240
they're destined to become
504
00:45:38,240 --> 00:45:40,373
among the largest reptiles on earth,
505
00:45:43,850 --> 00:45:45,683
if they can make it down the beach.
506
00:45:51,030 --> 00:45:53,540
The tiny flappers looking more like bath toys
507
00:45:53,540 --> 00:45:57,363
than ocean travelers must somehow make it to the sea.
508
00:45:59,160 --> 00:46:01,393
Instinct drives them in the right direction.
509
00:46:02,740 --> 00:46:05,390
They paddle along making little angels
510
00:46:05,390 --> 00:46:06,653
in the sand as they go.
511
00:46:10,640 --> 00:46:12,960
But even little ridges in the sand
512
00:46:12,960 --> 00:46:15,803
are like mountain ranges for creatures born to swim.
513
00:46:17,150 --> 00:46:18,573
Not all will make it.
514
00:46:25,800 --> 00:46:29,073
Some are imprisoned by debris washed up on the beach.
515
00:46:36,540 --> 00:46:39,300
Small and vulnerable out in the open,
516
00:46:39,300 --> 00:46:43,133
even tiny crustaceans can become lethal predators.
517
00:46:45,850 --> 00:46:49,037
Any dawdling, and the red ghost crabs strike.
518
00:46:56,470 --> 00:46:58,853
Much bigger shadows fall across their path.
519
00:47:01,960 --> 00:47:04,310
The keen eyes of a pied crow guide it
520
00:47:04,310 --> 00:47:06,703
to what it expects to be an easy meal,
521
00:47:14,178 --> 00:47:17,290
(dramatic music)
522
00:47:17,290 --> 00:47:19,963
though a Palm-nut vulture has other ideas.
523
00:47:27,622 --> 00:47:29,280
The onslaught is relentless.
524
00:48:04,540 --> 00:48:08,390
But turtles are born to a life of migration.
525
00:48:08,390 --> 00:48:10,160
The urge to begin their journeys
526
00:48:10,160 --> 00:48:12,943
compels them to tackle the challenges head-on.
527
00:48:18,050 --> 00:48:20,563
Only one in 1,000 will survive,
528
00:48:27,510 --> 00:48:31,113
but turtles, like many migrants, make it work,
529
00:48:36,590 --> 00:48:38,763
and they have for millions of years.
530
00:48:41,090 --> 00:48:43,693
Their instincts run deep to keep on the move.
531
00:48:47,370 --> 00:48:50,510
They're undistractible, answering to a call
532
00:48:50,510 --> 00:48:52,123
written in their DNA.
533
00:48:58,480 --> 00:48:59,773
They just keep swimming.
534
00:49:05,610 --> 00:49:09,670
Animals that migrate are some of the toughest on earth.
535
00:49:09,670 --> 00:49:12,210
They have learned to face hardship head-on
536
00:49:12,210 --> 00:49:14,920
to get the best out of their environment,
537
00:49:14,920 --> 00:49:19,030
and in doing so enrich the environment for others,
538
00:49:19,030 --> 00:49:20,433
including us.
539
00:49:30,920 --> 00:49:33,837
(victorious music)
540
00:49:41,462 --> 00:49:44,212
{\an8}(fish splashing)
42060
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