In order to increase the possibilities to have a job in city,the migrator's migrating, working and living decisions are basicly prepared and intentional rational behaviors.
Another marathon migrator, the Arctic tern, has long been credited with the longest migration for its annual round-trip flight between the Arctic and Antarctic — an estimated 40,000 km in total.
It happens from the smallest animals to some of the largest and the most abundant, in terms of biomass, migrators are typically small fish like bristlemouths and lantern fish that are following the vertical migrations of the zooplankton.
所有有情的怙主。
到工作的概率 ,他们的迁移和工作生
基本上是有目的、有准备的理性行
（精选双语）
南极之间的往返
行而长期被认为是
长的迁徙——估计总共有4万公里。
