Ducky: Up, Petrie! Higher! Higher like a flyer.
Littlefoot's mother: Dear, sweet, Littlefoot, do you remember the way to the Great Valley?
Littlefoot: I guess so. But why do I have to know if you're going to be with me?
Littlefoot's mother: I'll be with you. Even if you can't see me.
Littlefoot: What do you mean I can't see you? I can always see you.
Littlefoot's mother: I'll be in your heart, Littlefoot. Let your heart guide you.
Chosen answer: Littlefoot's mother has obvious grievous wounds on her neck and back. She also quite possibly has internal injuries as well. It's also possible that Sharptooth had many injuries as well, but was able to heal better or just fought through the pain because of hunger. Or perhaps he fell in ways that lessened injuries.
LorgSkyegon