每到春秋季节,很多动物都要成群结队定时长途迁徙,往来洄游。动物的迁徙行为大致可分为两种:一种是为了繁衍后代,另一种是为了生存。燕子从南方飞回筑巢的迁徙,海龟和大马哈鱼从大海回到出生地产卵的洄游,都是为了繁衍子孙的行为,统称为“回归”。 Every Spring and Autumn season, many animals should be in groups and long-distance migration in a regular basis, from the migration. Animal migration can be divided into two types: one is to breed offspring, and the other is to survive. The migration of swallows from the south back to nesting, the migration of sea turtles and salmon from the sea back to the eggs of their birth estate, all for the sake of breed, are collectively referred to as “return”.