but they're not the only commuters in here. 但它们并非这里的唯一住客

219. vast shoals of demoiselle fish return to the caves,
     大群雀鲷返回到洞窟中
220. which they use as a refuge from predators.
     这里是它们躲避天敌的地方
221. For these fish the caves are a night time retreat,
     对于这些鱼来说 洞穴是理想的过夜场所
222. but they're not the only commuters in here.
     但它们并非这里的唯一住客
223. There are other fish working to a different schedule.
     这里还有其它 按照不同日程表生活的鱼
224. The bigeyes are the equivalent of bats.
     大眼鲷相当于蝙蝠
225. Night feeders leave the cave each evening.
     它们每天晚上出洞觅食

来自《行星地球 第一季 第四集 Planet Earth S01E04 洞穴》第 222 行