Why Do Goats and Sheep Have Rectangular Pupils? 0 103

Such horizontal pupils are characteristic of prey animals, whose eyes are located on the sides of their heads. This feature allows them to have nearly a full circular view and to notice the approach of a predator in time.

The horizontally elongated pupil serves two key functions. Firstly, it lets in more light from the sides, significantly improving peripheral vision. This allows the left eye to see better what is happening on the left and behind, and similarly for the right eye. Secondly, the vertically narrow slit helps to focus more sharply on the horizontal contours of the landscape, which is especially important for accurately placing the legs while running over uneven terrain.

Overall, the rule that 'vertical pupils are found in predators, horizontal ones in prey' does hold true. For example, cats, as typical ambush hunters, have vertical pupils. However, according to the authors of certain studies, there are exceptions to this rule that have not yet received a definitive explanation and do not fully fit into existing theories.