Almost all people have ever seen a goat in their lives. But hardly anyone had the desire to look into her eyes. And if they looked, they would have experienced some surprise when they saw the shape of the pupils. Read on and you will find out what pupils the goat has and what is remarkable about them.
Pupil shape
Most often, people believe that the pupils of all animals are round. This opinion is formed by analogy with the human eye. But this is not so, in many animals the pupil has a completely different shape, for example, the pupils of the goat are located horizontally.
In the daytime, they look like a narrow gap. With expansion, the pupils of the goat turn into rectangles.
Why do I need a rectangular pupil
Due to this pupil shape, the goat’s viewing angle reaches 340 degrees without taking into account the rotation of the head. That is, when grazing, the goat has the opportunity to observe what is happening, without raising or turning its head. For comparison: a review of vision in humans - only 160-180 degrees with immobility of the head.
In the daytime, in strong light, the pupils of the goat are greatly narrowed and look just like gaps. The pupil constriction is mainly used to protect the goat's eyes from sunlight. With the arrival of dusk and night time, the pupils expand, taking the form of rectangles. In a very darkened room or with strong excitement in a goat, square pupils - this is achieved due to an even greater expansion of the pupil. Such a mechanism contributes to the same thing - a better view in the dark. A goat, like other animals with the same pupils, is able at night to notice a moving predator almost behind itself. This helps animals to notify other animals in the herd and hide, avoiding death.
The pupils of the goat give the animal the opportunity to feel relatively safe, because, having an almost circular vision and a tendency to live in the herd, a group of goats can graze calmly. When a predator appears in the field of view of at least one of the goats, the whole herd will have time to escape.
Interestingly, having such remarkable abilities to see around and in the dark, goats are unable to estimate the distance to various objects. These animals cannot even correctly determine the direction of movement, since spatial vision is very poorly developed in them.
Appearance of goat pupil shape
Such a pupil formed in goats and other artiodactyls millions of years ago. Initially, most likely, the pupils were round, but with constant exposure to the sun, the pupil began to narrow. As the animals feed with their heads lowered, the pupil begins to narrow in the horizontal direction in order to enable them to view the horizon without breaking away from food. Gradually, muscles formed inside the eye that cover the pupils of the goat to the gap in bright light. In the dark, these muscles relax, so that animals can eat at night with the same quality of vision.
Who else has a rectangular pupil?
Of domestic animals, sheep have pupils of the same shape. In the wild, almost all artiodactyls have this feature. In addition to artiodactyls, octopuses and mongooses possess a rectangular pupil, strangely enough: they also need to protect the pupil from bright sunlight for night life. And to control the horizon for these living organisms is also a vital task.
The various types of pupils reflect a different lifestyle, different habits and needs. To understand why and why pupils have a different shape, you just need to analyze what we know about living things. And then the horizontal rectangles of the goat, and the vertical crevices of cats, and the predatory squint of the shark will become clear. It is only necessary sometimes to look into the eyes of someone other than yourself.