Wing Commander CIC

An interesting thread about Klingons led me to wonder: Why do the Kilrathi exist? Ignoring the "iT's n07 r34l s0 i7 c4n b3 a3n371ng i7 w4n72 2 B!!!!!!!" argument, we haven't seen any Kilrathi agricultural development, and their entire culture is built upon war and the love of hunting. Without a stable agricultural base, which in turn leads to stable society, what makes them different from, say, the Mopoks?

Another point: are the Kilrathi truly wired for war and aggression, or is it simply such a major part of their culture they believe it to be true?