We know that many animals do not always stay in one place,birds,fish and other animals within a certain period of time to move from one place to another.They move for many reasons,provoked when the cold comes,many birds are migrating to warmer places for food.Salmon was born in fresh water to salt water but swim thousands of miles to go and live there.When the salmon in old age,will return to its birthplace of fresh water,and then come to an end.In Northern Europe there is a rat,when this increase in the number of rats is too congested,they left home to move to low mountain land.Sometimes they will always move to the beach,when they fell into the sea when the number of drowned rats.Recently,scientists of a lobster migration were studied.Each year,when bad weather comes,lobsters are often arranged in the beginning of a team went to sea,no one knows why they do this,and no one knows where they will go.So,sometimes we know why Why do humans and animals from one place to move to one place,but other times we do not know.Maybe just like bio-tourism.请翻译成地道的汉语翻译汉语？你给的不就是汉语么感觉汉语部分不够精美，悬赏10分译成汉语。我们知道许多动物并不总是待在一个地方，像鸟类、鱼类还有其他一些动物会在一定的时间里从一地迁徙到另一地。他们迁徙的原因有很多，当寒冷到来的时候，许多鸟儿都迁徙到温暖的地方去觅食。大马哈鱼出生在清澈的淡水水域里，但会不远万里游到咸水中去并在那里生活。当大马哈鱼年老的时候，他们又会回到他们的淡水出生地，然后寿终正寝。在北欧有一种老鼠，当这种鼠数量增长到多过于拥堵的时候，他们就会离开山里的家迁往平原地区。有时他们会一直跑到海边，当他们掉进大海的时候，许多老鼠都被淹死。近来，科学家们对一种龙虾的迁徙进行了研究。每年，当恶劣的天气到来时候，龙虾们总是排成长长的队伍开始向海里爬去，没有人知道他们为什么要这样做，也没有人知道他们将爬向何处。所以，有些时候我们知道人类和动物为什么会从一地迁徙到一地，但有的时候我们却不知道。也许他们只是喜欢旅游。