2016届高考英语三轮冲刺检测题：4_高考复习指南

2016届高考英语三轮冲刺检测题：4

　　At least the marmots are still hibernating. Several other animals have not been hibernating at all recently. Brown bears in the Spanish Cantabrian Mountains did not hibernate last year. In parts of the United States, chipmunks(花鼠)also skipped the hibernation period. The bears seem to have survived without losing many individuals. The chipmunks, however, were not so lucky. Many of the animals died of starvation during the winter.

　　The problem with animals waking up early, or skipping hibernation altogether, lies with the creatures’ metabolism(新陈代谢). When the animals hibernate, their metabolism drops significantly. The animals’ heart rate slows, and they require very little energy to live. When the animals awake from their winter slumber, their metabolism returns to normal.

　　But while their metabolism may be as active as it was before hibernation, food sources aren’t as available as they were before. A marmot may wake up when temperatures get warmer, thinking it’s spring, but plants will not have got the amount of sun they need to signal their spring period of growth. So until the plants grow, the marmots have no reliable food source.

　　Many scientists believe the problem will continue to get worse. In addition to changes in hibernation patterns, some believe that other animals will also begin to change their migration patterns or begin to give birth earlier. For many biologists, that’s a scary prospect. Terry Root, an animal expert at Stanford University, said, “I do think what we will be facing is the extinction of many species. ”