Oh, I thought the question was hypothetical (you know, like whether a vampire could beat a caveman in fight or something silly like that). Yeah, there are a thousand reasons not to mix species. I've seen that question so many times on all sorts of exotics forums and it's always been a bad idea.

The only successful interspecies cohabitation I've EVER heard of is between different species of garter or dekay's brownsnakes (all the same sex of course).