【题目】Whether the declining of bison was caused by the European American settlers.
【阅读】About bison, a kind of animal, something like cattle or horse. The passage suggests that the declining bison was due to the European American settlers:
1. When European American cross prairies, they hunted bison as food because there is no food in prairies.
2. They brought cattle and horses, which competed with bison for resources.
3. The evolving technology, especially guns, let hunters kill several bison in a short time.
【听力】The professor contradicts each of these three points:
1. The European American moved from east to west, but the bison decline in the western part of America. The pattern of how bison disappeared gradually was different from that of movement of European American.
2. Bison have double furs covering their bodies and unique head structure, which allow them to live in harsher and colder areas. The areas were unreachable for cattle and horses. How could different spices compete with each other in separate territories?
3. The advanced technology should not be blame worthy for the decreasing bison. The ancient methods are as effectively as guts. Skilled ancient American hunters could kill several bison with short intervals.