Washington, Jan 8 : A remarkable new discovery has shown the four-eyed spookfish to be the first vertebrate ever found to use mirrors, rather than lenses, to focus light in its eyes.
While the spook fish looks like it has four eyes, in fact it only has two, each of which is split into two connected parts. One half points upwards, giving the spookfish a view of the ocean - and potential food - above.
The other half, which looks like a bump on the side of the fish's head, points downwards into the abyss below.