When they opened the MGM casino in Reno when I was young, you could get your picture taken with the lion, looking like the movie intro. The lion was kinda tired and hungry, so the guy let me feed it meat on a stick like a qtip. He told me after the pic, what it was... disgusting.
A lion has a long history of being used for something so innocuous as story telling. Androcles, Arabian Nights, The Panchatantra, The Panchatantra. English Gentry uses the Lion Rampant and on seals and signets. It's even mentioned in the Bible a few times. It was just an obvious choice.