You Are Umasou

"Umasou is a great name! But what does it mean?"

You Are Umasou (Omae Umasou da na) is a 2010 Japanese animated feature film based on a Japanese children's book series of the same name by Tatsuya Yamanishi, published by Poplar.

The film follows a Tyrannosaurus Rex named Heart who was raised by a Maiasaura. Realizing he was different, he ventures out to find where he belongs. One day, Heart finds a baby Ankylosaurus who mistakes him for his father, accepting "umasou ((you) look delicious)" as his actual name. Originally intending to eat him, Heart comes to be genuinely concerned for Umasou's wellbeing as a familial bond develops between the two.

There is also a series of five-minute shorts lasting 20 episodes with every five episodes being an adaption of a book. All of them staring a male Tyrannosaurus Rex which is most likely not the same dinosaur. The first story is about the protagonist's relationship with Umasou. The second one is about the protagonist's relationship with an unnamed Elasmosaurus (named Pero Pero in the film). The third story is about the protagonist, Heart. The fourth story is about the protagonist's relationship with 5 baby Ankylosauri and their relationship with each other. The third one is the only one of the 4 stories where the protagonist is named. The film is essentially a combination of the first three stories retold with unaddressed issues being bought up (like how a Tyrannosaurus need to eat meat to live).

For similar carnivore/herbivore antics, see Arashi no Yoru ni.

Tropes used in You Are Umasou include:

Anti-Villain: One-eyed Baku is the leader of the Big Jaws and a Worthy Opponent to the protagonist. He's frequently shown being respectful towards Heart and once saved the land from "gluttonous long necks from the south", but when Heart and the Big Jaws start fighting each other, Baku is forced to take action against him.
Anxiety Dreams: Heart has them throughout the movie. They're pretty screwed up.
Award Bait Song: "Kimi to Irou Jikan no Naka De." It's even particularly Disney-esque, instead of anime-esque.
Bittersweet Ending: While the volcano eruption doesn't harm anyone, Heart can't really stay with his mother and siblings. He continues to live with Umasou, mostly alone.
Cartoon Creature: The dinosaurs in this movie aren't particularly realistic-looking, to the point where it's hard to figure out what some of them are. In particular is a strangely demon-horned carnivore, who's possibly a Carnotaurus, but just looks like some kind of demon.
- The T.rexes in the film walk upright have short rounded snouts, and have dorsal fins running down their backs making them look like a bizarre cartoony Expy of Godzilla.
Chekhov's Gun: When the land slightly gives way as Heart steps on it while looking for his mother - the same spot she later falls from.
- Also could be the focus on making his little arms stronger, when he later needs to pull his mother back up the cliff.
Children Raise You: Heart matures by looking after Umasou.
Cool Old Guy: Beckon, the old tyrannosaurus. He's too old to eat solid food, so he leaves Umasou alone.
Crystal Dragon Jesus: Somewhat. They're shown (particularly the mother) praying to the Egg Mountain.
Death of a Thousand Cuts: Heart employs this strategy in his fight against Baku, at least before the gloves come off.
Dramatic Irony: Heart never finds out who Baku really is, even though it becomes obvious to the audience relatively early on.
Eat the Dog: Heart initially plans on doing this with Umasou, but he ends up unable to resist the cute little guy.
Even Bad Men Love Their Mamas
Family-Unfriendly Death and Family-Unfriendly Violence: Some of the violence in the film is tame; however, many of the tyrannosaurs are shown killing other dinosaurs on screen, ripping them open and devouring flesh and guts, which mostly just looks like pink bubblegum. There's little blood.
Happily Adopted: One of the main thrusts of the movie. Heart was adopted by a plant-eater, and he adopts Umasou (another plant-eater) in turn. All of whom are pretty happy with the situation.
Hard Work Montage: Heart and Umasou are shown doing various types of training, including agility, headbutting, striking down trees and roaring, all to the tune of "Jump Kick, Tail Smash". Doubles as a Training Montage, since Heart is preparing Umasou to fight if something tries to eat him.
Interspecies Adoption: Two generations of it!
Ironic Nursery Rhyme: "Big Jaw," first introduced into the film as a lullaby sung by a giant sloth mother, is about how Tyrannosaurus will hunt you down and eat you if you cry.
Lighter and Softer: Despite its Family-Unfriendly Violence, the tone of the movie never really wavers.
Meaningful Name: Heart is a pretty soft-hearted dinosaur, no matter how much he tries to look tough. Later in the movie, when Heart is carrying an injured Umasou in his mouth, we see the outline of Umasou in his mouth, and the shape of his heart beating in his chest.
Non-Action Guy: Light, Heart's childhood friend and "brother". He is a plant eater, so he doesn't have any of the raw strength that Heart possesses, and is almost completely unremarkable.
Papa Wolf: Heart becomes increasingly protective of Umasou as the movie progresses, despite only seeing him as "tasty-looking" at first. When Gonza and the other Big Jaws try to eat Umasou, Heart flips out and attacks all of them - which leads to him being forced into exile for his crimes.
Ridiculously Cute Critter: Umasou. He's so cute that Heart confusedly starts talking to him as if he was his own son only a few seconds after seeing him.
Somewhere a Paleontologist Is Crying: It's meant to be an entertaining movie, not a biologically accurate one.
Soundtrack Dissonance: In one of the more violent scenes in the movie, Heart beats several other Big Jaws unconscious while a nursery rhyme plays in the background.
Unnamed Parent: Heart and Light's mother.
Vegetarian Carnivore: Heart, at first. When he finds out he actually enjoys the taste of meat, he's horrified since he thought he was an herbivore.