An octopus pupil is rectangular

octopus

Sheep, Goats, Octopuses and Toads have these rectangular shaped pupils. Typically classified as prey, these animals need to have a defense both day and night. But they don’t have vertical slits due to their need to survey their surroundings more accurately. The narrower the pupil in relation to the horizon, the greater the accuracy of depth perception is in the peripheral vision of the animal.