The pupils of a goat's eyes are square?

Yes, and only a few species have rectangular eyes. 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. The perception of depth must be considered with these animals who spend their time evading predators in a rugged terrain.

From The Evolution of The Rectangular Eye

http://www.science20.com/variety_tap/evolution_rectangular_eye