Is it possible for animals to commit moral wrongs? For instance, bottlenose dolphins are supposedly known to torment and even rape other dolphins. Many of the capacities once thought unique to humans (language, tool-use etc.) are now commonly ascribed to certain animals; but I've yet to see anyone claim that animals are capable of immorality.

It seems to me that in order for an agent to act rightly or wrongly, morally or immorally, s/he must be capable of having the concepts of right and wrong, moral and immoral: consequently, it seems to me that if certain animals were discovered to have the ability to have such concepts, then and only then could it be said that those animals were capable of right or wrong, moral or immoral actions. This is, it seems to me, an empirical question--albeit one that we may be unable to answer. But the mere behavior of animals does not, it seems to me, manifest the possession of such concepts.

I became a vegan two years ago, mainly motivated by emotional distress at the thought of the pain and suffering that animals go through to be killed/farmed. Now I justify this decision to others for health/social reasons, because I don't know how to justify it morally. I instinctively feel that to eat an egg, whether or not the hen was free-range, or even if I just found it outside, would be inherently wrong, but I can't quite articulate why logically. I suppose if pressed I'd say that all sentient beings possess rights, or at the right not to be treated as property, and farming violates this right. Does this stand up to scrutiny?

I can understand the concern that one might have about causing sentient beings pain--which may be a reason not to kill or slaughter animals--but it's not clear to me that one should go so far as to claim that all sentient beings have rights, or at least the right not to be treated as property--perhaps all sentient beings have a right not to be harmed, or subjected to pain, but it's not clear to me why all sentient beings have the right not to be treated as property. Hence it's not clear to me that this is indeed a good basis for the decision not to eat eggs. It seems to me that some other justification needs to be given for veganism.