Subspecies are often difficult to distinguish from one another .

区分不同的亚种是很困难的。

All five remaining tiger subspecies are endangered , and many protection programs are in place .

现存的5个老虎亚种都濒临灭绝，因此很多保护项目都在紧锣密鼓的进行中。

There were once eight tiger subspecies , but three became extinct during the 20th century .

老虎曾经有过一共8个亚种，但其中三个亚种在20世纪灭绝。

The sumatran rhinoceros is thought to have gone extinct in thailand and peninsular malaysia due to poachers working in crime rings , and two subspecies of african rhino have suffered similar fates .

人们认为，由于偷猎者以集团的形式非法偷猎，生活在泰国和马来半岛的苏门答腊犀牛已经绝迹了，而非洲犀牛的两个亚种也惨遭同样的命运。

All four subspecies of gorillas are listed as endangered or critically endangered by the international union for conservation of nature .

大猩猩的四个亚种都被国际自然保护联盟列为濒危动物或者极度濒危动物。