He loved the dinosaurs in it.
Before that, he loved the Jurassic Park movies and watched them over and over again like kids 15 years ago watched Barney.
My 11 year-old son is one of the most sensitive people you could ever meet, but he's not a wuss with stuff like involves animals eating each other or people.
For example, Mars Needs Moms freaks him out a little because he doesn't like the idea of missing mothers.