Any of various small,thickset rodents,especially of the genus Lemmus,inhabiting northern regions and known for periodic mass migrations that sometimes end in drowning.

• 旅鼠，一种体形短小但很健壮的啮齿目动物，尤指旅鼠属动物。它居住在北方地区，以其有时以淹死来结束生命的季节性群体迁徙而闻名。