How can a four-eyed fish have only two eyes?
While commonly named the four-eyed fish, this species of fish actually only has two eyes. However, their eyes have developed in a way that actually enables them to see above and below the water’s surface at the same time. Unlike most round eye pupils, this fish species has hourglass shaped pupils. This adaptation helps them avoid both aerial and aquatic predators.
Strangely enough, this interesting adaptation is not the only unique...