These species are believed to have disappeared because of natural causes, such as sudden changes in climate, competition with other species or catastrophic events such as earthquakes and volcanoes.

• 这些物种因为自然原因而被认为已经消失，这些原因包括诸如气候突变、与其他物种的竞争或像地震、火山爆发那样的灾难性事件等。