Thalia

I consider things that I feel define moral "personhood" such as sentience, self-awareness, ability to suffer, etc. This varies, and moral consideration, in my view should vary accordingly. I definitely don't have this down to a science, and it doesn't mean that I think humans can live without causing pain to other organisms. But to me, now that I have thought about what characteristics make something worthy of moral consideration, I know have to apply that more equally.

There is an interesting thought experiment, one which I have yet to come to satisfying conclusions about, which demonstrates the potential folly of using characteristics such as intelligence, reason, ability to speak, etc. as criteria for moral consideration (and actually, we use these traits as justifications for our treatment of non-human animals, not humans themselves. To do so would bring up images of Hitler, and other sick prejudiced practices) I notice that many of the answers people give are just attacks at the premise of the thought experiment itself. If one accepts the premise, the question is quite worthy of pondering.

ETA- as far as the "we are at the top of the food chain" well, I do not eat high on the food chain. We each choose where we eat on the food chain. To think we are "supposed" to be a certain place on the food chain sounds teleological to me, something I doubt many people here are fond of.