white mouse; white rat
Refers to albino laboratory mice or rats, or white-furred rodents in general.
They are breeding white mice in the laboratory.
I saw an experiment where a white rat ran through a maze.
Common mixed kanji-katakana spelling.
Search-only form; not a standard written variant.
Kanji spelling using 鼠; less common but still used.
Compound of 白 (しろ, 'white') and ネズミ (ねずみ, 'mouse/rat'). The katakana spelling ネズミ is common for the animal name.