Lemmings, small rodents of the arctic and subarctic regions of the Northern Hemisphere, have long been a byword for mass mindlessness and mass suicide.

• 旅鼠是一种生活在北半球北极区和亚北极区的小型啮齿类动物，一直以来人们流传着很多关于他们愚笨和自杀的笑话。