You think humans are the only beings in existence that kill other animals? No, almost every animal does it to survive. Granted we sometimes do it in some unorthodox ways, but when you're being but up with a meat cleaver or a pair of claws, you're not really caring about the difference.
Not to mention, humanity has been doing since the first time we figured out that meat was edible. Vikings, Romans, Indians, Americans, an entire race has been built on the notion that Darwinian philosophies have been a fact; that only the strongest survive.
Besides, humans are the only animals in the tire world, if not, the UNIVERSE that have a moral "conscience". If you were to ever be stranded on an iceburg for a week and the only way to survive until the rescue team comes is to eat a nice, succulent pig, I think you'd eat it wouldn't you? Where do the lines of right and wrong differ? Does eating another animal make you another animal? Of course it does, because YOU ARE AN ANIMAL.
Also, flora are living things to and you don't see them complain about being eaten. And don't give me that, "but plants can't feel pain" crap. Scientists have proved that trees and other plants have some degree of thought, so you're eating a living thing too, assholes.
Vegetarians, stop trying to be all morally rightous on us and announce to the world that killing animals is wrong and that the only way to live is by only eating fruits, grains and vegetables. Don't get me wrong, those things are good for your health too, and I love them as well, but for god sakes, either shut up or go out and eat a steak that isn't made of tofu.