Why goats and sheep rectangular pupils?
Pupil is, in fact, a diaphragm, which, narrowing or expanding, regulates the entry of light on the retina. In addition, its size and form affect the field of view and the quality of the image obtained on the retina. Different animals – depending on the ecological niches occupied by them, location in the food chain, lifestyle and type of power – these characteristics differ from each other.
Herbivore Hoofed Animals (goats, sheep, cows, antelope, horses and t. D.) The food chain is always victims for any predators. In accordance with this, their visual analyzer forms visual information, and its brain processes from the point of view of "Prey Mentality". Any fast moving object, even if it is unless it is visible, it may well be an attacking predator, so any unexpected movement immediately causes a herbivore protective reflex: defense and / or flight.
All herbivores have large eyes, a little ripples located almost on the sides of the head. It provides the widest field of view. For example, the total width of the view of the horse is approximately 350º. Thus, the horse does not see the narrow sector directly behind the population. (In the article "My Planet" "The world is not our eyes" you can read and even watch how the world is seen, bee, cat, etc.)
In the daytime, with strong lighting, the eyes of goats and sheep have a narrow slot; In the dark, the pupil expands, acquiring the view of rectangles or even squares.
Rectangular, or rather, the horizontal oval pupil from herbivores just helps to see as wide as possible panoramic painting around him. Due to the stretched form of pupil the goat, for example, has an angle of review almost 340 °, that is, in the pastiber, it quietly observes what is happening around himself, not even raising the heads.
In the daytime, with strong lighting, the eyes of goats and sheep have a narrow slit; In the dark, the pupil expands, acquiring the view of rectangles or even squares. Such a mechanism contributes to the same – better review in the dark. Goat, like other animals with such pupils, can notice a moving predator at night almost behind. When a predator appears in the field of view, at least one of the goats, the whole herd has time to escape.
According to the latest studies, a long horizontal pupil also improves the quality of the objects of objects ahead and behind the animal, which facilitates the rapid movement on uneven or highlands, and also helps the eye to capture more light along the surface and less dazzling light above the head. In addition, watching grazing animals in the zoo, the researchers discovered that the eyes of animals rotate in such a way that the line of pupils always remained aligned horizontally, even when the animal heads are omitted vertically down.