2020年12月英语六级（第3套 · 含听力）仔细阅读 Passage 2

Imagine that an alien species landed on Earth and, through their mere presence, those aliens caused our art to vanish, our music to homogenize, and our technological know-how to disappear. That is effectively what humans have been doing to our closest relatives—chimps (大猩猩).
Back in 1999, a team of scientists led by Andrew Whiten showed that chimps from different parts of Africa behave very differently from one another. Some groups would get each other's attention by rapping branches with their knuckles (指关节) while others did it by loudly ripping leaves with their teeth. The team identified 39 of these traditions that are practiced by some communities but not others—a pattern that, at the time, hadn't been seen in any animal except humans. It was evidence, the team said, that chimps have their own cultures.
It took a long time to convince skeptics that such cultures exist, but now we have plenty of examples of animals learning local traditions from one another.
But just when many scientists have come to accept the existence of animal cultures, many of those cultures might vanish. Ammie Kalan and her colleagues have shown, through years of intensive fieldwork, that the very presence of humans has eroded the diversity of chimp behavior. Where we flourish, their cultures wither. It is a bitterly ironic thing to learn on the 20th anniversary of Whiten's classic study.
'It's amazing to think that just 60 years ago, we knew next to nothing of the behavior of our sister species in the wild,' Whiten says. 'But now, just as we are truly getting to know our primate (灵长类) cousins, the actions of humans are closing the window on all we have discovered.'
'Sometimes in the rush to conserve the species, I think we forget about the individuals,' says Cat Hobaiter, a professor at the University of St. Andrews. 'Each population, each community, even each generation of chimps is unique. An event might only have a small impact on the total population of chimps, but it may wipe out an entire community—an entire culture. No matter what we do to restore habitat or support population growth, we may never be able to restore that culture.'
No one knows whether the destruction of chimp culture is getting worse. Few places have tracked chimp behavior over long periods, and those that have are also more likely to have protected their animals from human influence.
Obviously conservationists need to think about saving species in a completely new way—by preserving animal traditions as well as bodies and genes. 'Instead of focusing only on the conservation of genetically based entities like species, we now need to also consider culturally based entities,' says Andrew Whiten.