Yup, I had a friend who worked with musk oxen, and he had a story about a bunch of kids who thought it would be cool to climb in with them in the middle of the night cause they look so harmless... only they're huge, and territorial. They barely made it out in time.
The Shamu Adventure actually has video that shows killer whales in their element - attacking seals on the beach. It also used to show killer whales eating penguins, but they got too many complaints about that video (which, funny enough, is far less violent than the scenes left in) so it was removed from the show here in San Diego.
-Kirsten