Things that go bump in the night!!!

Im pretty sure we have rats or something living under the house. We live in a queenslander and have nothing but storage/garage underneath. I hear them running around and fighting. I think we have had one for a while but now i know there are more. im listening to them crashing about just under the floor boards now!
I dont know what to do, i dont want to kill anything, i have enough trouble killing the ants that raid my kitchen! but dont want to be over run...how can i get rid of them in a nice way or without killing anything that isnt a rat!!!

updated question.....
OK....i saw them last night,went down when they were banging around and there one was...but im pretty sure its not a rat. For a start it was light grey. It had a long thinish pink tail and its face wasnt long and pointy like a rat, more squashed. and its ears were bigger and a little more stuck out. Still quite big, about small rat sized, Is it just that im used to seeing fancy rats in the pet shop or is it a different animal?? Do you think i could trap them and then have the 'dealt with' if they were rats or relocated if they were something else, somthing native.

*bump*

I don't know how to get rid of them without being mean and actually killing them.

But if you would prefer, get the pest control guys in so they have their deaths on their soul and not yours.. LOL

pest control is best , we had pigeons and the pest man fed them pelltes that made them high and fly away and eventaully die somehwere else , pmsl my cat ate some and was off her face for about a day . the pest man will know whats the best way to get rid of them , as they are a pest and qld is better off with out rats , i know its hard to "need" to kill /get rid of them but unless they are a domestic pet then the bad points about wild ferral rats out weight the good .

give some ppl a call and ask how they get rid of rats and pick the one thats not so harsh , most chemicals they use these days are family friendly too :)

updated question.....
OK....i saw them last night,went down when they were banging around and there one was...but im pretty sure its not a rat. For a start it was light grey. It had a long thinish pink tail and its face wasnt long and pointy like a rat, more squashed. and its ears were bigger and a little more stuck out. Still quite big, about small rat sized, Is it just that im used to seeing fancy rats in the pet shop or is it a different animal?? Do you think i could trap them and then have the 'dealt with' if they were rats or relocated if they were something else, somthing native.

Hmm, they could be a little native marsupial. Maybe ring a native animal sanctuary or parks and wildlife and run it by them and see what they say.

sounds like they are possums to me.

I think you can get possum traps from the local council so you can relocate them.

well, that what I thought at first, we have ringtails in the tree in our garden but they we too small i think...unless you get mini possums?? :)