Loss of habitat is to blame, specifically, the lack of the pocket of air between snow and ground called the “subnivean space.” There lemmings winter and give birth to prodigious litters of young.
生
环境的缩小是一个原因，更主要的是它们
和地面之间被称为“下空间”里得不到
护，有些旅鼠会冬天生下数量惊人却
法活的小旅鼠。
