The entire population of these cave angel fish 世界上所有的洞穴天使鱼

248. These troglodytes from Thailand
     泰国的这些穴居动物
249. are possibly the most specialised creatures on Earth
     可能是地球上最奇特的动物
250. for they live only in cave waterfalls.
     因为它们只生活在洞穴瀑布中
251. The entire population of these cave angel fish
     世界上所有的洞穴天使鱼
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

来自《行星地球 第一季 第四集 Planet Earth S01E04 洞穴》第 251 行