根据资料卡的内容介绍下面这种濒危动物的相关信息以及我们应该如何保护这种动物。

Name：Yangtze alligator(扬子鳄)

Live in：The Changjiang River

Food：birds, frogs, mice and so on

Number in the past：Many

Number now：About 130 in the wild

What can we do to help them?

Keep the water clean.

Don't hunt them for food.