北极熊英文介绍.ppt

The largest terrestrial carnivorous animal Polar bear some pictures about Polar bear The polar bear is a bear native largely within the Arctic Circle encompassing（围绕，包围;） the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world‘s largest land carnivore（食肉动物） and also the largest bear Polar bears In its existent space, it is the topmost food chain. It has thick fat and hair to stay warm, its white appearance on white snow is good protective coloration, and it can on land and sea, so it can catch food in the arctic in this extremely harsh（严酷的） climate. Ecological role The polar bear is the?apex predator（顶端食肉动物）?within its range. Several animal species, particularly?Arctic Foxes?and?Glaucous Gulls, routinely scavenge（清除） polar bear kills. The relationship between ringed seals（环斑海豹） and polar bears is so close that the abundance of ringed seals in some areas appears to regulate（调节） the density（密度） of polar bears, while polar bear predation in turn regulates density and reproductive success of ringed seals. The?evolutionary pressure?of polar bear predation on seals probably accounts for some significant differences between Arctic and Antarctic seals. Because polar bears play an important role in Arctic environment, scientists feel that polar bear can be a good indicator of the health of Arctic environment. So, we can say that by protecting polar bears, we are protecting the whole Arctic ecosystem. Global warming has an impact on the ice. The ice is melting quickly in north and south pole. And that have a bad influence on polar bears. Due to the global warming, Arctic ice began to melt, the polar bear’s home has been destroyed, the prey is also a corresponding reduction in Polar bears are in danger, we must take measures to protect the kind of beautiful and lovely animal. Because it is the treasure of nature. Physical character The polar bears claws are short and stocky . the teeth are larger and sharper Polar bear fur consists of de