聽音頻：​

　　如不能正常播放，點擊此處下載聽力mp3>>>

　　進入專題：2015年聽力風暴來襲，英語四級每日一聽！ 

　　A team of scientists has found a surprise element to the social structure of baboons: democracy. The animals live in groups with a single male leader. But, apparently, obedience to the leader is not always the rule.

　　Margaret Crofoot is a primatologist at the University of California, Davis. She led the scientists in their study of wild baboons at the Mpala Research Center in Kenya.

　　The team placed GPS devices on 25 baboons. They recorded the animals' movements for two weeks. The devices provided about 20 million points of data.

　　In this file photo taken on Jan. 16, 2015, a  baboon feeds on plants in Lake Manyara National Park on the outskirts of Arusha, northern Tanzania. (AP Photo/Mosa'ab Elshamy)
In this file photo taken on Jan. 16, 2015, a baboon feeds on plants in Lake Manyara National Park on the outskirts of Arusha, northern Tanzania. (AP Photo/Mosa'ab Elshamy)
The scientists examined the data by measuring the distance between two baboons. How that distance changed provided a picture of how the group moved as a whole.

　　Ms. Crofoot says she was surprised that the baboons did not follow the group's lead, or dominant, male. Her team found that the majority ruled the group's movements. The animals followed the direction set by the most baboons. Ms. Crofoot says the results show that dominant individuals only direct what the group does some of the time. She says at other times the process is more egalitarian and democratic.

　　Individual baboons decide where to go by looking around to see where others are going. Looking to one's neighbors when deciding where to go is not unusual for birds and fish. But it was not expected for baboons.

　　Scientist Crofoot says when the baboons could not compromise about a direction, they often had to stop and think about the issue. This meant losing time for eating, playing, socializing and other activities.

　　So, the urge to move with the crowd may be the greatest evolutionary invention in support of unity.

　　I'm Caty Weaver.

　　Maia Pujara reported this story from Washington. Caty Weaver adapted it for VOA Learning English. George Grow was the editor.

　　聽力技巧：2015英語四級聽力九大攻略技巧｜四方面基礎關鍵

　　2015年緊跟命題組老師丁雪明老師備戰，首推精品VIP班，45小時一步直達英語四級！不過免費重學，馬上試聽！