Set 82 million years ago in what will be Kansas, this documentary focuses on a young female Dolichorhynchops as she navigates the perils of the Western Interior Seaway in her first annual migration. There, she has to avoid the various predators of the inland sea, including the large predatory fish Xiphactinus, sharks, and the giant mosasaur Tylosaurus.
Tropes:
- Always a Bigger Fish: Both a Hesperornis and a Squalicorax are eaten by the large mosasaur Tylosaurus while in pursuit of their prey, a small fish and the protagonist respectively.
- Anachronism Stew: Averted for the most part, the one exception being the Gorgosaurus we see early on in the documentary. Lythronax would have been a better option, but it wasn't named yet at the time.
- Behemoth Battle: A 29-foot Tylosaurus finds himself in the sights of a larger individual of the same species. The skirmish concludes with the death of the smaller tylosaur.
- Big Eater:
- Tylosaurus is capable of eating any creature smaller than it.
- Xiphactinus swallows a 6 foot long fish called Gillicus, which proves to be its downfall.
- Bizarre Alien Locomotion: Both Dolichorhynchops and its larger relative Styxosaurus swim with four paddle-like limbs unlike any animal alive today.
- Deadly Dodging: Dolly moves out of the way of a charging Xiphactinus, only for the fish to ram head-first into a Gillicus, which it eats.
- Fantastic Fauna Counterpart: Some of the creatures shown have parallels in our modern oceans.
- The Pteranodon are analogous to large seabirds like albatrosses or frigatebirds.
- The Dolichorhynchops are reminiscent of pinnipeds, owing to their limb-driven swimming and their agility underwater.
- The Xiphactinus resemble giant, oceanic tigerfish.
- The Cretoxyrhina and Squalicorax are ecological analogues to great white and tiger sharks respectively.
- Fiendish Fish:
- A Xiphactinus is shown pursuing Dolly.
- Two sharks, a Squalicorax and a Cretoxyrhina pursue the female protagonist and her mother respectively.
- Gentle Giant:
- The Styxosaurus, although dwarfing the Dolichorhynchops pose no threat to them and are happy to feast on fish instead.
- The Tusoteuthis, being a squid as big as the giant squid of today, passes underneath the Dolichorhynchops pod without causing any trouble.
- The giant turtle Protostega feasts on squid and leaves Dolly (who passes by it) alone.
- Giant Squid: The Tusoteuthis is a squid that approaches the length of modern-day giant squids.
- Gory Discretion Shot: When the Cretoxyrhina attacks Dolly's mother, the scene immediately cuts to above the water, where only a pool of blood is seen.
- Missing Mom: Dolly loses her mother to a Cretoxyrhina.
- Perilous Prehistoric Seas: The Western Interior Seaway is this, being home to predators like Tylosaurus and Xiphactinus.
- Seldom-Seen Species: Every creature with the possible exception of Pteranodon is relatively unknown to mainstream culture.
- Threatening Shark: A Squalicorax and a Cretoxyrhina pursue the female protagonist and her mother respectively.
