They looked at almost 7,000 species of vulnerable, endangered, or critically endangered animals that appear on the IUCN red list.

他们研究了 IUCN 红色名录中出现的近 7,000 种脆弱、濒危或极度濒危的动物。

The polar bear's " vulnerable" status on the IUCN Red List of endangered species — less severe than " endangered" or " critically endangered" — does not accurately reflect their plight, the authors argue.

北极熊在国际自然保护联盟的濒危物种红色名单上属于“脆弱”等级——没有“濒危”或“极危”那么严重，研究作者指出，这一等级没有准确反映出它们的困境。