Blue's pose is inspired by those hilarious old rubber dinosaur toys that lined the mouths of even herbivorous dinosaurs like Triceratops and Stegosaurus with sharp pointy teeth. So nostalgic! (The ones I had as a kid even glowed in the dark.)
While I've got you here, I want to recommend The Secret of the Kells, a beautiful animated movie from the producers of The Triplets of Belleville that I'd never heard of until a day or so ago and now I'm shocked that it snuck up on me. Check it out!