Coasts

* Title
* I
* II
* VI

***“ A pregnant Tuarangisaurus is in distress, and her young calf can sense it, as she travels waters that are home to the ocean's deadliest predators. ”***

― The official Apple TV+ episode synopsis for *Coasts*
***Coasts*** is the first episode of the first season of Prehistoric Planet.

## Segment I: *Tyrannosaurus* Family

* Hell Creek Formation, Montana - South Dakota, USA
* Western Interior Seaway, USA

**Coasts**, Segment I
**Setting**

* Hell Creek Formation, Montana - South Dakota, USA
* Western Interior Seaway, USA

***“ The southern shores of the great inland sea that splits North America, and the tracks of the land's top predator. A Tyrannosaurus rex taking a swim. Hollow, air-filled bones and powerful hind limbs make T. rex very effective swimmers. This is an adult male, with his young family. His offspring are now just old enough to follow him on a journey to one of the many offshore islands that fringe this coast. ”***

― **David Attenborough**, *Coasts*
The first segment of the episode takes place by the southern shores of the Western Interior Seaway, an inland sea that splits North America in half, with the tracks of a dinosaur left in the sand. The creature that left the footprint is nowhere on land, however. In the sea, an adult *Tyrannosaurus* is seen swimming, having smelled meat on an offshore island just a short distance from the coast, with his five young offspring following close behind.

***“ It's a short enough crossing, but it can still be a dangerous one... a Mosasaur, a giant marine lizard over twice the size of a tyrannosaur, and weighing over 15 tonnes. It's the largest predator on the planet. Turtles are normally on a mosasaur's menu, but this brood would make a welcome snack. An adult T. rex, even in water, can still defend itself very effectively, but the young must stay close... ”***

― **David Attenborough**, *Coasts*
However, a mosasaur, taking notice of the tyrannosaur family, turns around in hopes of snatching one of them. The adult tyrannosaur briefly looks down in the water to gauge how close the mosasaur is, prompting him and his five children to swim faster. The mosasaur, aware that the adult *T. rex* is still capable of defending itself in the water very effectively, sets its sights on the one *T. rex* hatchling lagging behind the rest. As they approach the shore, the mosasaur closing in on them, the hatchling that is lagging behind screeches more as its panic grew greater, until it got dragged down beneath the waves, the mosasaur flicking its tail and turning around just as the rest of the tyrannosaur family reached the coast of the offshore island. The patriarch of the family gets up and faces the sea, realizing that one of his five offspring was taken away.

***“ Tyrannosaurus rex often lose at least two-thirds of their original brood of 15 or so in the first year. Now, there are only four. ”***

― **David Attenborough**, *Coasts*
With nothing more than can be done, he turns to the smell that drew his attention to the offshore island. Ignoring the giant two-tonne turtles crawling around, having arrived to the beach to lay their eggs, the *T. rex* walks to an already-dead turtle, turns it over, and crushes through its belly with his five-ton bite force. When his chicks try to get a taste, however, he drives them off with a growl, intending for them to learn to hunt for food on their on their own.

***“ The beach, however, doesn't look very promising. But as the evening approaches, things start to change. Baby turtles are beginning to hatch from the sand, and rush down to the sea. The young T. rex have been brought to an ideal training ground. Hatchling turtles are the perfect size for a novice to tackle. ”***

― **David Attenborough**, *Coasts*
The four surviving juveniles at first simply run around the beach, even playing around and riding a giant turtle at one point. As evening approaches, the turtles eggs buried in the sand hatch, and the young turtles make their way to the sea. One young tyrannosaur at first plays around with these turtles, stomping some of them into the sand, and getting scared off by the waves as they take a turtle hatchling into the sea. Their parent still refuses to share the dead turtle he's eating, so one of the juveniles decides to go after a baby turtle, only to be fought off by one of its siblings, which steals and eats the baby turtle for itself, leading to a game of chase. The segment ends with more of the newly-hatched turtles getting swept by the waves into the sea.

## Segment II: Ouled Abdoun Basin

***“ It's especially rich here in the North Atlantic, where huge shoals of fish come close to the shore. One kind of animal thrives in such places and forms immense colonies. Flying reptiles, pterosaurs. Here, on the beaches of North Africa, there are seven different species of them. They come here to feed, to rest, and to raise their young. ”***

― **David Attenborough**, *Coasts*
In the second segment of the episode, which takes place on the shores of Northern Africa, a colony of the *Tethydraco* is seen on a beach. Within the colony are a few *Alcione* and *Barbaridactylus*. The pterosaurs are on the beach to rest and raise their young. One *Tethydraco* hatchling is seen wandering around, though its mother quickly ushers it back in place to keep it from wandering too far from the nest. The concerns of the parents are justified, for, wandering the beach, is an opportunistic predator.

***“ Tethydraco are well-adapted to spend their time on the ground, and not only make their nests here, but stay to protect their brood. And their young certainly need protection... The dagger beak of Phosphatodraco. The nine foot-tall predator that stalks through these colonies, looking for a chance to snatch an unguarded hatchling. ”***

― **David Attenborough**, *Coasts*
The *Tethydraco* clack their beaks to keep the larger pterosaur away from their nests and chicks, though the *Phosphatodraco* remained undaunted, completely disregarding these warnings as it continued patrolling through their colony.

***“ But some pterosaurs are less well-adapted to life on land. They have a slightly different nesting strategy. They make their nests where they will attract less attention from predators. Isolated cliffs like this are ideal. Pterosaur eggs are leathery, and can easily dry out, so they need to be covered. Beneath this pile of seaweed, something is stirring. A tiny Alcione hatchling, just a few inches high, and weighing less than two ounces. Their mothers left the eggs here about two months ago. Calling to each other synchronizes hatching; there is safety in numbers. ”***

― **David Attenborough**, *Coasts*
Meanwhile, in some offshore islands, newly-hatched *Alcione* chicks emerge from beneath piles of seaweed. As they chirp, even more of them hatch and come out. By instinct, hundreds climb to the top of the cliff, doing short test flights as their wings slowly form up.

***“ Hatchlings from hundreds of nests gather on the clifftop to prepare for their first flight. But their wings are still unformed. The bones of the long finger that supports their wing membrane must first straighten and lock together, and that will take some hours. But they can't stay here for long... Their bones are extremely light, up to 90% air, and that makes the effort needed to take off much easier. Even so, test flights are essential. There will only be one chance to get it right when the time comes to launch. ”***

― **David Attenborough**, *Coasts*
The updrafts formed by the cliff edge provide favorable conditions for them to fly all the way to their destination, the mainland. Even so, there is initially an air of hesitance, until finally, one hatchling flies off, prompting the rest to follow suit. They're not heading for the colony on the beach, but the misty forest on the cliffs beyond the beach.

***“ Barbaridactylus. Powerful predatory pterosaurs that normally catch fish, but the hatchlings are too good to miss. One way to take evasive action is to simply fold their wings and drop. But losing height will make it harder for them to reach the forests. ”***

― **David Attenborough**, *Coasts*
Unfortunately, the journey there is not straightforward. Sensing an easy meal, three *Barbaridactylus* swoop in and snap up some of the hatchlings in midair. The juvenile *Alcione* fold their wings and drop, momentarily evading their predators at the cost of lost height. Some end up flying too low to the ocean, and are easily grabbed by the *Barbaridactylus*.

***“ A crash landing in the colony. It's no place for a hatchling on its own. ”***

― **David Attenborough**, *Coasts*
One unlucky *Alcione* hatchling crashes down on the beach, attracting the attention of the *Phosphatodraco* prowling the colony. The *Tethydraco* look on as the *Alcione* hatchling tries to stand up, while the opportunistic azhdarchid closes in on it, clacking its beak in satisfaction before grabbing the hatchling, devouring it as it screeched its last. The *Tethydraco* give one last glance as the predator swallowed and savored its meal, serving as a reminder of what fate could befall their chicks should they be left unguarded, before one turned its attention back to the *Alcione* that are still airborne, trying to escape the *Barbaridactylus*.

***“ A lucky survivor from the first wave of hatchlings, still heading in the right direction... sanctuary. Of the hatchlings that left the stack, few get as far as this. But for them, this forest offers all the shelter and food that a young pterosaur needs. For the next five years, this will be their home, then, they will be large enough to join the adults catching fish out on the open ocean. ”***

― **David Attenborough**, *Coasts*
One hatchling is shown, still being pursued by a *Barbaridactylus*. It manages to finally reach the cover of trees, prompting the predator to stop just short of the forest and fly off at last. This survivor, among a few others, gather in the safety of the trees, resting and flapping their wings as they watch the open ocean. The segment ends with a shot of five adult *Alcione* flying across the ocean, giving the hatchlings a glimpse of the future ahead of them.

## Segment III: *Tuarangisaurus*

  **Coasts**, Segment III
**Setting**
Tahora Formation, North Island, New Zealand
***“ Some marine animals that spend all their lives fishing out at sea must occasionally visit the coast for a very particular purpose. In the waters off the drowned continent of Zealandia, a long journey is coming to an end. These are Tuarangisaurs, a type of huge marine reptile nearly 30 feet long. ”***

― **David Attenborough**, *Coasts*
In the third segment of the episode, in the seas covering the sunken continent of Zealandia, a *Tuarangisaurus* brings her six month-old calf to one particular bay in the South Pacific, were many others of their kind gather.

***“ Males also gather here to display to females. But for now, courtship is not the female's first priority. This bay has something that few others can provide. Pebbles that are particular smooth, hard, and rounded. They've been worn by the action of river water, but they're hard to find. Here, however, in the pool at the bottom of a waterfall, there are plenty of them. And the Tuarangisaurs can take their pick. ”***

― **David Attenborough**, *Coasts*
Males raise their necks vertically above the water in a bid to impress females in the area. But first, the mother *Tuarangisaurus*, along with several others, congregate by a waterfall dropping off the cliff of the rocky coast, forming a rainbow where the freshwater from above meets the rocks and the sea down below. The elasmosaurs have come to collect pebbles smoothened by the river, using their snouts to dig the ideal stones from the shallow floor of the coast.

***“ They then do something rather remarkable. They swallow them. They need the stones to act both as ballast and as gizzard stones, "gastroliths" which will remain in their stomachs to grind up their unchewed food. For a youngster, learning to swallow pebbles for the first time isn't easy. It takes a little practice. But it's also a chance for his mother to find a suitable mate amongst the males. ”***

― **David Attenborough**, *Coasts*
The mother elasmosaur leads her young down to the stones at the bottom of the waterfall, intending for him to learn how to collect gastroliths. As the calf struggles to learn how to properly pick up and swallow stones, the mother leaves him to it and proceeds to find a suitable male, engaging in courtship in the open waters. By the time she has returned, her calf has finally learned how to swallow pebbles properly.

***“ For the calf, at last, success. Now, he will swallow as many as he can, and, as he grows, he'll return here for more. It's time for the family to leave the coast and head back out to sea to feed. And for the young Tuarangisaur, that is an important step on the road to adulthood. ”***

― **David Attenborough**, *Coasts*
The segment ends with the elasmosaurs departing from the bay of ideal gastroliths, setting off for the open ocean to search for food as the sun, hanging high from the sky, shines down on them.

## Segment IV: *Mosasaurus*

**Coasts**, Segment IV
**Setting**
Tethys Ocean, Europe
***“ In southern Europe, where the Atlantic meets the great Tethys Sea, coastal life perhaps reaches its greatest diversity. Rising sea level means that there are countless submerged islands covered with sponges, clams, and corals. Corals take advantage of the sunshine in these shallows, forming partnerships with algae that grow within their tissues. They collect tiny particles of food floating in the ocean currents. Myriads of these marine creatures encrust the solid rock. But one rock here appears surprisingly bare. Beyond is a sheer dropoff and the deep sea, home to oceanic predators, and danger for unwary reef fish... ”***

― **David Attenborough**, *Coasts*
The fourth segment of the episode takes place by the shores of southern Europe. By the submerged, coral-encrusted islands in the shallow waters, an old male *Mosasaurus hoffmannii* visits a bare rock, momentarily scaring a pycnodont fish.

***“ ... but this pycnodont fish has little to fear. This is Hoffmann's Mosasaur, the ocean's deadliest predator, but he's not here to eat, he's come to be cleaned. Mosasaurs are giant lizards, and have both a lizard's forked tongue, and, during the mating season, a lizard's colorful skin. Now, it's time to shed old skin. ”***

― **David Attenborough**, *Coasts*
Once the many inhabitants of the reef realize that the mosasaur wasn't there to eat, however, they begin to clean him, with various fish and cleaner shrimps picking off scraps from the mosasaur's teeth as well as the old skin he was shedding off, revealing that his face and back have turned a striking shade of red to make him more attractive during the mating season. The *Mosasaurus* rolls around on the rock, allowing the fishes and shrimps to clean even its belly. Since he was resting by the surface of the sea, the old *Mosasaurus* can poke his head out of the water and breathe in some air.

***“ A rival, a younger male challenging for this territory. The old male is heavier, over 15 tonnes, but his rival is more nimble. When they are as evenly matched as this, these fights can be lethal. Mosasaurs have been found with the shattered teeth of rivals embedded in their skulls. ”***

― **David Attenborough**, *Coasts*
Unfortunately, his relaxing moment at the cleaning stations is cut short when a younger male, eager to claim his territory, suddenly lunges at him, grabbing him by the neck while he's disoriented in an attempt to pin him to the rocks. Both mosasaurs retreat and circle back towards each other, barely colliding head-on, with the older male managing to halt the younger male by grazing his left side. The two pull back and collide again, with the younger male grabbing his rival's snout, trying to pin him down. As the old male struggles, the young male continues to assault him, momentarily grabbing his right front fin, but mostly attempting to crush his neck and bash him against the rocks. Momentarily fending off his rival by biting his neck and pushing him down in turn, the old male rushes up to the surface to take a breath.

***“ The old male snatches a breath. Now, he has the advantage. By dragging his rival down, he could drown him. ”***

― **David Attenborough**, *Coasts*
His strength replenished, the old male grabs his rival by the throat. When he tries to break free, the old male grabs his snout, dragging him down the walls of the submerged island, all the way down to the depths, where clouds of sand obscure both of them from view. For a moment, all is quiet. The younger male eventually emerges from the clouds, swimming to the left, with no sign of the older male anywhere. Then, at last, the old male emerges upward from the depths, triumphantly returning to the surface to breathe in once again.

***“ The old male has triumphed. For now, at least, this reef is still his territory ”***

― **David Attenborough**, *Coasts*
The segment ends with the old male leisurely keeping his head above the water as the view zooms out to reveal the great extent of the Tethys Ocean under a cloudy sky.

## Segment VI: *Tuarangisaurus* and *Kaikaifilu*

***“ Back in the shallow waters of Zealandia, large groups of Tuarangisaurs have come together. They propel themselves with all four fins, and travel almost effortlessly to find the fish shoals that gather here in summer. Occasionally, they break the surface to gulp air before continuing on their underwater flight. ”***

― **David Attenborough**, *Coasts*
In the sixth and final segment of the episode, in the shallow waters of Zealandia, large pods of *Tuarangisaurus* have come together to find the shoals of fish that gather in that area during the summer.

***“ But one female is not swimming with her usual grace. She and her two year-old calf are lagging behind the rest of the group. She's moving rather laboriously, and that has not gone unnoticed. A deadly hunter. Kaikaifilu. The apparently-stricken female is a tempting target. Diving to deeper water might make her less vulnerable. For the calf, trying to distract the mosasaur is a dangerous game. But it's buying time. The mother and calf are not entirely alone... ”***

― **David Attenborough**, *Coasts*
One female, more sluggish than usual, lags behind the group, with only her two year-old calf to keep her company. Her laborious movement is noticed by a *Kaikaifilu*, which closes in on her, since she appears to be the easiest target to kill. She attempts to escape to deeper waters, while her calf charges at the mosasaur to harass and distract it.

***“ These individuals may be related, and it's in all their interests to drive Kaikaifilu away. ”***

― **David Attenborough**, *Coasts*
Just when the calf got the mosasaur's full attention, enraging it enough to really commit to pursuing the juvenile plesiosaur, at least 4 - 5 of the members of the *Tuarangisaurus* pod circle back and assault the mosasaur, snapping at it and forcing it to leave.

***“ This is the reason for the female's apparent distress; she's pregnant. And now, after a one-and-a-half year pregnancy, a baby. Over ten feet long, nearly half the length of its mother, one of the biggest babies of all time. It needs to get to the surface to take its very first breath. ”***

― **David Attenborough**, *Coasts*
With the hunter gone, the sluggish *Tuarangisaurus*, which turns out to be pregnant, can finally give birth in peace. Making herself known to her newborn calf, the mother *Tuarangisaurus* guides the baby to the surface, where they both take in a breath of air.

***“ This young Tuarangisaur could live for eighty years. Now, supported by her family, she can take her place as a predator in one of the richest habitats on Earth, the seas around the coasts of our Prehistoric Planet. ”***

― **David Attenborough**, *Coasts*
With this, the newborn calf swims alongside her mother, who rejoins the rest of the pod as they swim around, continuing to catch fish by the cliffs of a tall, rocky landmass, the last bits of Zealandia still jutting out of the sea.

## Uncovered Segment: Could *T. rex* Really Swim?

  **Could *T. rex* Really Swim?**
**Subject**
The evidence supporting the idea of *T. rex* being capable of swimming, much like other large animals in the modern day.

**Experts**
Dr. Darren Naish
Footage from the first segment of the episode is used for this Uncovered segment, dedicated to discussing whether *T. rex* can really swim. Its large skull, huge teeth, and evidence of an acute sense of smell serve are excellent proof of its prowess as a hunter, but what's being asked for is proof regarding its ability to swim. The answer lies in the muscular bird-like hind limbs of the theropods, good for walking and running. It is therefore argued that the kicks generated by these same, powerful legs can help *T. rex* cross large bodies of water.

***“ And in the fossil record, there is direct evidence for exactly this. Score-like marks known as swim traces, created when the claws of a two-legged dinosaurs like T. rex scraped sediment on the bottom of lakes, rivers, and the seabed as they swam. ”***

― **David Attenborough**, *Prehistoric Planet: Uncovered - Could T. rex Really Swim?*
CT scans also helped reveal that many theropod bones were hollow, which would have helped their massive bodies float. This helps serve as further evidence that *T. rex* is an excellent swimmer, and, using this ability, it can expand its feeding opportunities, as seen on the show, when it swam to an offshore island to feed on a dead turtle. To help dispel doubt, comparisons are made with several large animals alive in the modern day. Footage of swimming horses, elephants, ostriches, and emus are shown, proving that, even today, some of the heaviest animals can regularly go out for a swim.

***“ In the modern world, the animals that are most similar to T. rex in general body shape are giant, flightless birds like ostriches and emus. And, perhaps surprisingly, these animals are very good swimmers. There are places where these birds make sea crossings, sometimes of several miles, so they can reach offshore islands and find new sources of food. ”***

― **Dr. Darren Naish**, *Lead Scientific Consultant*
Even so, the ability to swim does not make *T. rex* completely safe. With giant predators like *Mosasaurus* prowling the seas, ready to snatch them (most especially the more vulnerable juveniles) at any time, *T. rex* would have only been brief visitors of the prehistoric oceans, for, though it is the "Tyrant Lizard King", mosasaurs are still undisputedly the masters of the waves.

## Fauna

*Tyrannosaurus rex**Mosasaurus hoffmannii*Protostegid*Tethydraco regalis**Phosphatodraco mauritanicus**Alcione elainus**Barbaridactylus grandis**Tuarangisaurus keyesi*PycnodontScaphitid*Kaikaifilu hervei*
## Trivia

As revealed by concept art, the episode was originally titled "High Seas" during the early stages of development.