I am in need of a rodent that does not have a gall bladder (other than the rat). I know of a mastomys natalensis but do not know of any US based supplier. Any help on locating any small rodent that doesn't have a gall bladder would be appreciated. Removal of the gall bladder won't work in our experiments. Thanks. Jeff Silverman (Jeffs at elsie.cni.nih.gov)