If you look into the crystal clear, honest eyes of a sheep or goat, you will notice that her pupils have J. Lewis‑Stempel. The Sheep’s Tale: The story of our most misunderstood farmyard animal rectangle shape.
This may cause you confusion. Why do we need flirting with geometry when the most perfect figure is a circle? However, in fact, the reason why goats, sheep and other ungulates have rectangular pupils is related to their lifestyle.
Before we move on to goats and sheep, let's figure out what a pupil is. This is the opening in the iris of the eye through which light passes before it hits the retina. It can C. J. Murphy. The functional significance of crescent‐shaped pupils and multiple pupillary apertures / Journal of Experimental Zoology have different shapes: round, vertical, horizontal or rectangular. And also changes the size to adjust the amount of light caught by the eye.
As it is easy to notice, goats and sheep are herbivores. No, of course, they bite off the finger on occasion J. Belanger, S. T. Bredesen. Storey’s Guide to Raising Dairy Goats, 4th Edition they can easily, but usually they don't eat meat after all. These ungulates prefer stunted vegetation that is on the ground.
Rectangular pupils help to expand the field of view and better navigate in space in search of food.
The round pupil, like in primates, has the smallest surface and allows the animal to see most clearly and accurately what is in front of it. However, it restricts vision on the sides. Because of him, animals whose way of life is connected with the search for food on earth could not J. Lewis‑Stempel. The Sheep’s Tale: The story of our most misunderstood farmyard animal would really consider the space around.
Therefore, nature has endowed goats and sheep with rectangular pupils. Thanks to them, ungulates see well in the horizontal plane — not only find food, but also detect potential danger from the sides. They are capable of J. Lewis‑Stempel. The Sheep’s Tale: The story of our most misunderstood farmyard animal react quickly to any threats and escape in time if a wolf suddenly comes to the pasture.
In addition, rectangular pupils allow you to more effectively capture light coming from different directions. It is also an important feature for those who live in an open area.
However, even animals with a similar lifestyle may have pupils of different shapes J. Lewis‑Stempel. The Sheep’s Tale: The story of our most misunderstood farmyard animal . For example, horses have round ones. The fact is that these animals are more active and can run fast. Therefore, they need to see well in different directions, not just in the horizontal plane.
And yes, rectangular pupils can boast C. J. Murphy. The functional significance of crescent‐shaped pupils and multiple pupillary apertures / Journal of Experimental Zoology not only livestock — for example, deer, elk, hippos, they are the same. And also for toads and octopuses, even though they are predators.