I seem to recall that an English teacher somewhere along the course of my education had indicated that when referencing distinct types of a word, e.g. a computer mouse and the mammal, it would be proper to refer to them as "two mouses" rather than mice.
Is that actually the case? If so, where are the lines commonly drawn - consider for example observing a Canada Goose and a Greylag Goose as a more gray area or perhaps the tooth from a mouth versus a tooth from a saw blade as something quite distinct.