I ask because I was just reading about toxoplasmosis, a protozoan infection that reproduces in cats but can live in most mammals, and it has some really interesting side-effects, such as: - Antisocialism - Reduction in novelty-seeking - Increased jealousy - Slower reflexes - Reduced aversion to cat-related smells - ADD and Schizophrenia All of which has two major effects: 1. reduced attractiveness to women, and 2. more time to spend playing with (or, if you're a mouse, getting eaten by) cats. That would be one hell of a symbiosis, if cats carry an infection that cause other mammals to dislike going outside and prefer spending time near cats. http://en.wikipedia.org/wiki/Toxoplasmosis Anyway, I bring it up because you can get it if you have an outdoor cat that you sometimes have to clean up after, and you don't wash your hands perfectly afterwards. It makes me wonder, because I've been bitten and scratched and licked by cats my entire life, and I can identify with quite a few of the symptoms. Doesn't mean they're related, but it's possible.