Many zoos in the United States have undergone radical changes in the philosophy and design. All possible care is taken to reduce the stress of living in captivity. Cages and grounds are landscaped to make gorillas feel immersed in vegetation, as they would be in a Congo jungle. Zebras gaze across vistas arranged to appear (to zoos visitors, at least) nearly as broad as an African plain.
Yet, strolling past animals in zoo after zoo. I have noticed the signs of hobbled energy that has found no release—large cats pacing in a repetitive pattern, primates rocking for hours in one corner of a cage. These truncated movements are known as cage stereotypes, and usually these movements bring about no obvious physical or emotional effects in the captive animal. Many animal specialists believe they, are more troubling to the people who watch than to the animals themselves. Such restlessness is an unpleasant reminder that—despite the careful interior decoration and clever optical illusions—zoo animals are prisoners, being kept in elaborate cells.
The rationale for breeding endangered animals in zoos is nevertheless compelling. Once a species falls below a certain number, it is beset by inbreeding and other processes that nudge it closer and closer to extinction. If the animal also faces the whole-scale destruction of its habitat, its one hope for survival lies in being transplanted to some haven of safely, usually a cage. In serving as trusts for rare fauna, zoos have committed millions of dollars to caring for animals. Many zoo managers have given great consideration to the psychological health of the animals in their care. Yet the more I learned about animals bred in enclosures, the more I wondered how their sensibilities differed from those of animals raised to roam free.
In the wild, animals exist in a world of which we have little understanding. They may communicate with their kind through "language" that are indecipherable by humans. A few studies suggest that some species perceive landscapes much differently than people do; for example, they may: be keenly attuned to movement on the faces of mountains or across the broad span of grassy plains. Also, their social structures may be complex and integral to their well-being. Some scientists believe they may even develop cultural traditions that are key to the survival of populations.
But when an animal is confined, it lives within a vacuum. If it is accustomed to covering long distances in its searches for food, it grows lazy or bored. It can make no decisions for itself; its intelligence and wild skills atrophy from lack of use, becomes, in a sense, one of society’s charges, completely dependent on humans for' nourishment and care.
How might an animal species be changed—subtly, imperceptibly—by spending several generations in a per:? I posed that question to the curator of birds at the San Diego Wild Animal Park, which is a breeding center for the endangered California condor. "I always have to chuckle when someone asks me that," the curator replied.
"Evolution has shaped the behavior of the condor for hundreds of years. If you think I can change it in a couple of generations, you’re giving me a lot of credit."
Recently the condor was reintroduced into the California desert—only a moment after its capture, in evolutionary terms. Perhaps the curator was right; perhaps the wild nature of the birds would emerge unscathed, although I was not convinced. But what of species that will spend decades or centuries in confinement before they are released?
1.The primary purpose of the passage is to （）
2.The primary function of the second paragraph is to show that（）
3. In the fourth paragraph, the author's most important point is that animals in the wild（）
4.Which of the following best describes the relationship between the fourth paragraph and the fifth paragraph?
5. In paragraph 5 “charges” most nearly means（）
