You are Umasou
Instantly fell inlove with this movie. A T-Rex named "heart" raised by a plant eater. And face the consequences of being different while growing up.
I saw a badly edited video of this movie on Facebook and decided to try to find it on Youtube as it looked like a indie Youtube creation to me.
I saw the full length video on Youtube and watched it. It turns out to be a full length Japanese movie about a plant-eating mother dinosaur finding a strange egg and taking care of it, until it hatched to be meat-eater baby which obviously would be a problem for her and her family. She named him "Heart".
Growing up, Heart will discover and deal with the consequences of being different, specially compared to his close brother, who is a real plant-eater and finding the truth and leading himself to what he is suppose to be.
After developing himself, he comes back and saves his plant eater family from danger, by being dangerous himself. On one scene, his brother asks him if he eats meat. And his answer is yes, but at least he gets to choose what (who) to eat. His eyes during this scene is really one of the best expression I saw.
To me, this tackles the reality of life. To be harmless is not a virtue. Better be someone who can do harm, but have wisdom when to use it. Be a monster with a heart.
(Disclaimer: Please support the official release. I do not endorse watching Youtube instead of official release, but this particular movie doesn't have accessible official release on my country.)