1.
Overcrowding is another reason that animals travel.
过度拥挤是动物迁徙的另一个原因，
2.
used of animals that do not migrate.
用来指不迁徙的动物。
3.
resident fauna.
无迁徙习性的动物群
4.
used of animals that move seasonally.
用来指随季节迁徙的动物。
5.
Many migrating animals such as birds, whales, and butterflies use magnetism for navigation.
很多迁徙的动物，如鸟、鲸鱼和蝴蝶用地磁来导航。
6.
Some creatures find safety in numbers and travel in flocks, schools or herds.
有些动物群集而居，迁徙时成群结队以求安全。
7.
force certain animals to move from one place to another,
迫使某些动物不得不从一个地方迁徙到另一个地方，
8.
After several incidents of attacking campers, all bears were emigrated from the park.
发生几起宿营者袭击动物的事件之后，所有的熊都从公园迁徙走了。
9.
about half of all invasive species are moved by accidentl
约有一半的入侵物种的迁徙纯属偶然。
10.
Extract from Java Brucea Fruit Inhibits Cell Migration Mediated by PDGFRβ;
鸦胆子提取物抑制PDGFRβ介导的细胞迁徙
11.
Two-Way Flow of Population Marks Free Migration
人口双向流动是“自由迁徙”的标志
12.
On the Migration on the Eurasian Grassland in the Early 11th Century;
论11世纪初期欧亚草原上的迁徙运动
13.
Ambient temperature is one of the most important factors that restrict cold-blood vertebrate distribution, existence, breeding, migration and so on.
环境温度是制约冷血脊椎动物分布、生存、繁殖、迁徙等活动最重要的生态因子之一。
14.
Researchers have found that migrating animals use a variety of inner compasses to help them navigate.
研究人员已经发现迁徙性动物可以借助各种各样的体内罗盘来校正方向。
15.
Small animals such as bushy tailed rats, chipmunks and pinion mice are being chased upslope by rising temperatures, until they at last have no place to run.
而一些小型的动物，如花栗鼠，因为温度不断的升高而必须往高处迁徙，直到没有地方可走。
16.
Scientists are trying to learn how animals know that they must move to keep alive.
科学家们正在努力地探索动物是怎样知道它们必须迁徙才能生存下来的奥秘。
17.
A lack of rain in some areas and floods in other areas are harming the land and have led to the displacement of people and wildlife.
一些地区的干旱少雨和另一些地区的洪灾正对土地造成损害，并且导致人口和野生动物的迁徙。
18.
it was easy to control the danger of this as travel was still quite slow.
由于迁徙过程缓慢，物种入侵的威胁便容易控制。