Why do goats have rectangular pupils?
The human pupil has a round shape and everyone is used to it. Also, no one is surprised by the vertical pupils of pet cats. But an urban person who rarely encounters rural living creatures is almost always interested in the pupils of goats. If you look into the eyes of a goat or a goat, you will see that their pupils are as close as possible in shape to a rectangle. Why was it so intended by nature?
Goat pupils look not easy unusual, but even creepy. Combined with the horns, beard and wild roar of goats, they gave these animals a bad reputation in the Middle Ages. No wonder the Prince of Darkness was often portrayed as a goat. But the strange eyes of these animals are not an element of the image, but a necessity.
The pupil is needed to absorb light, due to which an image is formed on the surface of the retina. To make absorption as efficient as possible, the pupil is always black. The expansion and contraction of the pupil, which are responsible for miniature muscles, make it possible to change the amount of light. In low light, the pupils of people and animals dilate, and in bright light, on the contrary, they narrow.
Pupils in nature are very different. But mammals can only have three types: round, upright, and rectangular (oval). In herbivorous mammals, the pupils are always rectangular and horizontal. This is their form in cows, horses, sheep, deer, elk, antelope, buffalo and even pigs.
Together with the location of the eyes on the sides of the head, such pupils provide their owners with the maximum viewing angle. Therefore, they better see the predator approaching them. The goat covers 320-340 degrees with its vision. Therefore, it is incredibly difficult to get close to her and go unnoticed. For comparison, it is worth saying that cats see around only 200 degrees, and humans - 180. Yes, in the dark, the rectangular pupil of herbivores turns into an oval or round one.
Vertical and round pupils are common in predators. The slit-like shape is typical for those who lead a nocturnal lifestyle, and the round one is for those who hunt during the day or are equally active day and night. Vertical pupils in small cats, many reptiles and amphibians, and round pupils in large cats such as lions and tigers, as well as wolves.