What kind of animal nibbles on a tomato plant?

[organichris]

Something has been nibbling on one of my tomato plants. I'm quite confident that it isn't an insect. It has to be an animal. I would guess a rabbit, although I thought rabbits didn't eat tomato plants. I'm about ready to bust out the old sling shot and kill some rabbits. They make for pretty decent stew.

I went out one day and noticed one of the biggest leaves had been removed. About three days later the leaf on the opposite side had also been removed. Is it a rabbit or something else?