showers are fine. i take mine in with me and it doesn't bother them. i find it even helps in bonding. it was theorized that the steam helps calm them just like children and stressed adult humans. i don't have the temperature scalding but it is warm. i don't hold their heads under the water either. we just share the space. if their head doesn't get wet then there is no chance of ear infection or phnueomonia. and even getting a few splashes of water at the bottom of the tub its unlikly any harm would come of it. its not like the droplets are all that strong by the time they reach the bottom of the tub. i've never had a problem with a rat getting sick by sharing a shower with me and i've found they prefer the showers with me when bathing them then a bath on their own