It’s obvious that humans are fundamentally different from other animal species. It’s not so easy, though, to identify the traits that make human beings so special. Scientists realized long ago that other animals make tools, play jokes and even have a sense of justice and altruism—all things we once thought were unique to our species.
Now a paper in the journal Current Biology has added another behavior to the list of what other animals share with us—and this one isn’t quite so charming. After years of field observations in Uganda’s Kibale National Park, John Mitani of the University of Michigan and several colleagues have concluded that chimps wage war to conquer new territory.
"We already knew that chimps kill each other," says Mitani. "We’ve known this for a long time." What scientists didn’t know for certain, at least in cases in which groups of chimps banded together to kill others, was why. One hypothesis, advanced more than a decade ago by anthropologist Richard Wrangham, was the idea of territorial conquest; circumstantial evidence from both Gombe and Mahale national parks in Tanzania bolstered the theory.
In Mahale, for example, male members of one group mysteriously vanished, and another group then expanded into what had been their land. In Gombe, an existing group dissolved into civil war, resulting in killings and land takeovers.
What’s especially chilling about the observation is that the murder rate appears to be so high. The anthropologists couldn’t be certain of how big a band the victims belonged to because they weren’t used to a human presence and thus couldn’t be accurately counted. But even a conservative estimate suggests that the death rate is significantly higher than you would see in war between human hunter-gatherer groups.
Mitani isn’t oblivious to the lesson some people might draw from the study. "Invariably, some will take this as evidence that the roots of aggression run very deep," he says, and therefore conclude that war is our evolutionary destiny. "Even if that were true," says Mitani, "we operate by a moral code that chimps don’t have."
Apart from that, he points out, the Pan troglodytes chimps he studies are one of two subspecies. The other is called Pan paniscus, also known as bonobos, and, says Mitani, "the latter, as far as we know, aren’t nearly as aggressive with respect to intergroup relations. Yet they’re equally close to us." That means that if we’re wired for warfare, we’re wired for peace too. Ultimately, the route we choose is still up to us.
What problem did the anthropologists meet in studying the chimps（）
A. They have no clue as to why chimps grouped to fight
B. There is not enough evidence to prove Wrangham’s hypothesis
C. They can’t confirm the number of the chimps involved in the war
D.There’s not enough people to participate in the field observation
参考答案：C
解析：
[试题类型] 推理引申题。
[解题思路] 题干对人类学家(anthropologists)在研究黑猩猩时所遇到的问题提问，由此定位到文章第五段。该段第二句指出，人类学家不能确定遇难的黑猩猩所属的群体有多大(the anthropologists couldn’t be certain of how big a band the victims belonged to)，即人类学家不能确定有多少黑猩猩参与战争，故选项[C]“他们不能确定参战的黑猩猩的数目”最符合文意。
[干扰排除] 文章第三段提到“科学家不能确定为什么黑猩猩会互相残杀”，但后文接着指出，人类学家理查德·兰厄姆为其原因提出了一种假设，并且该假设被大量证据间接地证实了，故不能说科学家对黑猩猩互相残杀的原因一无所知，排除选项[A]。第三段未句指出，在坦桑尼亚冈贝国家公园和马哈尔尔国家公园发现大量的证据间接地证实了这一假说(circumstantial evidence...bolstered the theory)，此处的theory即兰厄姆的假设(Wrangham’s hypothesis)，故选项[B]错误。原文并没有提到没有足够的人手参与到野外观察中，排除选项[D]。