十年前，在扬子江中存在了2千万年的白鳍豚宣告功能性灭绝。不过近日，中国的某些动物保护人士却认为自己看到了这种已灭绝的海豚。
Chinese conservationists believe they may have caught a rare glimpse of a freshwater dolphin that was declared functionally extinct a decade ago having graced the Yangtze river for 20 million years .
功能性灭绝