在北欧的挪威、瑞典等地,有一种奇特的旅行鼠,这种鼠繁殖能力惊人,平时它们群居生活,最令人奇怪的是他们每隔三四年就会留下几个同伴,其余数十万乃至百万只就会成群结队地进行大规模的迁移。旅行鼠的大迁移主要在夜间进行,白天进食休息,晚上跋山涉水,路上遇到河沟也不回头,大批 In Norway, Sweden and other places in Northern Europe, there is a peculiar rodent, which has amazing breeding power and usually lives in groups. The most curious thing is that they leave a few companions every three to four years, and the rest Tens of thousands or even millions will only migrate in large numbers in groups. The major migration of the rats is mainly carried out at night. During the day, they eat and rest. They wading through the mountains in the evening. The river ditch does not turn back on the road.