And the Belizean white crab is another creature that is unique to just one cave system. 而伯利兹白蟹是另一个 洞穴生态系统中的特有物种

252. seems to be restricted to just two small caves.
     可能只存在于两个较小的洞穴中
253. It's the same story with other troglodytes.
     其它穴居动物也是同样的情况
254. There may well be less than a hundred Texas cave salamanders in the wild.
     世界上可能只有不到100只 野生洞栖童态河溪螈
255. And the Belizean white crab is another creature that is unique to just one cave system.
     而伯利兹白蟹是另一个 洞穴生态系统中的特有物种
256. Living in perpetual darkness
     由于一直生活在黑暗之中
257. they have all not only lost the pigment in their skin,
     它们不仅失去了皮肤色素
258. but also their eyes.
     眼睛也退化了

来自《行星地球 第一季 第四集 Planet Earth S01E04 洞穴》第 255 行