1. 野原・牧草地に生息し、短い尾とがっしりした体に目立たない耳を持つキヌゲネズミ科、(特にハタネズミ属の)様々なネズミのような各種の小型齧歯動物(any of various small mouselike rodents of the family Cricetidae (especially of genus Microtus) having a stout short-tailed body and inconspicuous ears and inhabiting fields or meadows)