My patronus, hmm, I'll be honest. It would probably be similar to what my animagi form would be. Either a horse, for obvious reasons. A crocodile, since I'm very tough, I'm territorial (protective of my property and friends), and I have a wide grin.
Or it could be a mountain lion/puma/cougar. I love hiking through trails in the forest and I move fairly swift through there are well. I also have long nails, and can climb trees and rocky slopes, (while wearing the appropriate footgear of course), and I have a surprisingly high pitched scream.