Fight for Life

Fight for Life is the fourth episode in the BBC series Planet Dinosaur. The episode first broadcast on 5 October 2011.

Plot
The episode begins with John Hurt talking about the discovery of "Predator X".In a database scene,a Tyrannosaurus skull is compared to a Pilosaurus skull.Some Kimmerosaurus are seen hunting angel sharks.However,a Pilosaurus ambushes the plesiosaurs,but they manage to escape to water too shallow for the enormous pilosaur.The episode then cuts to North America,where a herd of Stegosaurus and Camptosaurus coexist in a mutually beneficial relationship: the Camptosaurus are lookouts,while the Stegosaurus provide protection.The herbivores are eating but a Allosaurus is nearby.Some Camptosaurus spot the Allosaurus and bark to alert their herd (composed of both Stegosaurus and Camptosaurus) of danger, but a Stegosaurus walks through their field of vision, blocking their view. When it walks away, the predator has dissapeared. When the Camptosaurus let their gaurd down and resume eating, the Allosaurus makes its ambush and runs after the Camptosaurus, but they are too fast.The Allosaurus focuses on the slower Stegosaurus.The Allosaurus targets a smaller Stegosaurus and bites its plates.Then,the Allosaurus bites the stegosaur's neck.However,a larger Stegosaurus whacks the Allosaurus with its thagomizer,puncturing a hole in the carnivore's bones.The Allosaurus,panting and bleeding,falls over as the Camptosaurus and Stegosaurus escape.The Allosaurus surivives.John Hurt then talks about the Allosaurus vs Stegosaurus evidence.Back at the Jurassic Seas,Pilosaurus chases the Kimmerosaurus but is unable to use its full power in swallow water,allowing the Kimmerosaurus to escape.Later,another Allosaurus stalks a pair of Camptosaurus and chases one.the Allosaurus kills the herbivore with a bite to the neck.John Hurt then talks about how Allosaurus killed.Just as the Allosaurus takes a bite,a Saurophaganax arrives and bites the smaller Allosaurus in the neck.The Allosaurus leaves and the Saurophagnax begins to feast.The episode then cuts to the Jurassic Seas,where the Pilosaurus is still chasing the Kimmerosaurus.A Kimmerosaurus is feeding near the ocean surface.Pilosaurus attacks from below and bites the Kimmerosaurus,killing it.The Pilosaurus eats half the Kimmerosaurus,leaving the other half of it to sink to the seafloor.The episode ends with the narrator stating that creatures like Pilosaurus "ruled the oceans for more than 100 million years".