Clinton,
The bull will fight to stay alive, just as every organism will. However, what it does not have is a concept of mortality - of the nature of death and its inevitability. That is what sets human beings (as far as we know) apart from the rest of the biosphere - the fact that we know we are going to die (or, to paraphrase Beckett, that we give birth astride the grave).
It's why we invented God, but maybe that's a thread drift too far. :^) (For that same reason - the fundamental difference between us and other species - I prefer to think of human responsibilies rather than animal rights, but again that's risking drift...)