We don't have to kill other animals to survive. We have been inspired and have created other means of sheltering and feeding ourselves that don't necessitate us to resort to murder. That's why I'm a vegetarian. And it's strange. As advanced as we are now, we give much less respect to what we kill than our ancestors, who had to kill animals did. Ancient tribes respected the life that had to be lost to sustain theirs. They were grateful to the animal and didn't waste a part of it. But nowadays, we raise animals on factory farms, who have no other life than being prepared for food. They are abused and slaughtered. I'll start faulting animals for their part in the food chain when I see a tiger herd up a bunch of antelope and keep them all around in horrible conditions until he's ready to kill them.
I think the main reason more people aren't vegetarians, or at least the main reason that I'm not one anyway, is that it deprives us of many of the necessary nutrients that we as humans need to survive. I have a friend who is 100% vegan, and she is very thin, with dry yellowed skin; she's always tired, and she has to take a handful of vitamin pills every morning, as well as a bottle of water wherever she goes, because her diet basically consists of pita bread and hummus (at least at lunch, anyway). It just seems like meat was meant to be a natural part of our diet, otherwise those who abstain from it wouldn't have to resort to artificial means to get their essential nutrients.