Can survival of the fittest accomodate morals?

Interesting topic. Certainly evolution developed some sort of moral behavior in animal kingdom. But what I couldn't figure out yet is the conscious in us. For example, we some how value moral acts and there is a sense of content and satisfaction after it. Also when you do an immoral act there is a sense of gilt after it. I don't believe any animal have such feelings. This sense is so strong that people commit suicide because of it. For example we sometimes see a murderer goes and turn himself in or kill himself just because of this sense. Or where is that blush after lying comes from?!