Many wild animals are facing the danger of extinction, because the environment that they are living in has changed greatly。

For example，with the developmet of cities, the using of insecticide and serious pollution, their living areas have become narrowcr and narrower。

Many of the wild animals, now are confronted with food crisis。 At the same time, man is killing off species just for getting their fur, skin, horns, teeth and meat。

In order to protect our resources of ecology，people should realize that the loss of any species is at least the loss of source of knowledge and a source of natural beauty。

There fore, measures of the following should be takenpollution standards are made to keepdown poisons；killing off certain rare species is prohibited，national parks should be set up as wild life，reserves。

Only if we human beings take some drastic measures can wild animals be preserved。

The polar bear is the world"s largest land carnivore, also known as polar bear, naive. Skin is black, because the hair is usually transparent so that the appearance of white, there are yellow and other colors, great size, ferocity.

Polar bears considerable human vision and hearing, but their sense of smell is very sensitive, is seven times the dog; when running the fastest speed of up to 60km / h, 1.5 times the world 100 meters champion. As global temperatures rise, gradually began to melt the Arctic ice floes, polar bears former home has been a certain degree of damage is likely to become extinct in the near future, human needs protection.