It is thought that the cephalofoil, that hammer-like head, in the hammerhead sharks has evolved to improve their vision. The positioning of their eyes on the ends of the hammer allows the sharks to have a binocular vision, i.e. the field of view from the two eyes overlaps. Also, the hammerheads can see 360 degrees in the vertical plane, allowing them to see other animals above and below them all the time.