Not dinosaurs

["Nicholas R. Longrich" <longrich@phoenix.Princeton.EDU>]

        I know this has nothing to do with dinosaurs, but it's really 
annoying me and I was wondering if anybody knew. Why do some rats have 
hairless tails? The only thing I could guess at is that they might have 
had ancestors that used the thing like a cuscus or opossum does, as a 
prehensile climbing device (I know some rats are handy climbers) but that 
doesn't seem to make a lot of sense... Just wondering.
        thanks,

-Nick L.