Though the swifts depend on the cave for shelter, they never stray further than the limits of daylight, as their eyes can't see in the dark. However, deep inside the cavern, other creatures are better equipped for subterranean life. A colony of bats is just waking up, using ultrasonic squeaks to orientate themselves in the darkness. Night is the time to go hunting.


尽管雨燕依靠洞穴遮蔽，他们却必定在日落前归巢，因为他们的眼睛无法在黑夜中看清事物。然而洞穴深处是一群更适应地下隐秘生活的居民。一群蝙蝠刚刚醒来，他们运用超声波在黑夜中确定自己的方位。夜晚是狩猎时间。