Why did the near extinction and migrations of wild animals occur?

为什么会发生野生动物濒临灭绝和迁徙的现象？

youdao

I have help getting protection now, because I was near extinction.

现在我受到了保护，因为我正濒临灭绝。

youdao

And one antelope in particular, the Arabian Oryx, which was hunted to near extinction, now has a wild population of over 1,000.

特别地，被猎杀至近乎灭绝的一种羚羊——阿拉伯羚羊，现在野生数量已超过1000只。

youdao

Lake sturgeon were once plentiful but were fished to near extinction in many places by the early 20th century.

WSJ: Standing Guard for the Sturgeon

Once hunted to near extinction, some 3m fur seals now inhabit the island.

ECONOMIST: Icebergs ahoy | The

In other parts of Africa, primal scenes like these are almost impossible to witness because the animals have been hunted to near extinction.

BBC: The rhino wars of central Kenya