@shortstories Not in the wild, of course. Their instincts make them kill for food. But in captivity they seem to be fine when kept on a vegetarian diet, though they live a less stressful and less active / dangerous life. And according to this, supplements are necessary, just as with humans.
As a young earth creationist, I believe a vegetarian diet only works on non-corruptible bodies. So that's a significant caveat.