Goats’ pupils are horizontal, unlike ours and animals such as snakes and cats; even in the shape of a thin rectangle.
When researchers from UC Berkeley and Durham University, who studied these eerie and unusual-looking horizontal slits, examined the pupil shape of a total of 213 land species, including goats; they had the opportunity to see more clearly how the ecological niche shapes the eyes.
Pupil shape is linked to the ecological niche or role of the animal.
Some of the herbivores that are the target of carnivores have this type of pupil to protect themselves from predators. Horizontal slit pupils, which offer a wider field of view, are an advantage of evolution.
Even while grazing, they can check for predators that might be lurking around. This peculiar shape provides a panoramic view that can detect intruders approaching from various directions. So they can act sooner when they need to make an escape plan.
When they lower their heads to graze, their eye slits are always parallel to the ground.
Using computer models, the researchers say that eyes on two different sides produce a much wider field of view than eyes like ours.
Goats can rotate one eye more than 50 degrees, which means they can rotate 10 times more than a human eye.
Goats have a vision of 320-340 degrees, while humans have 210 degrees of vision. While monocular (one eye sees) and binocular (both eyes) vision in goats is 20-60, binocular vision in humans is 114 horizontal and 150 vertical.
Moreover, horizontal pupils also improve the image quality of objects just in front of the animal.
Thanks to this clear front view, goats can move quickly over rough terrain. This type of elongated pupil shape reduces chromatic aberration in high light, improving focus and improving the image quality of ground objects.
So why do predators like snakes and small cats have vertical pupils?
Because in this way, they can evaluate the distance better and it will be easier for them to jump on their prey.
Some other predators such as lions and tigers have round pupils.
The reason for this is “closeness to the ground”. Since the need for depth perception decreases as they move away from the ground, taller predators such as tigers have round pupils.
There is a greater need for depth perception on the ground.
They can expand and contract, altering depth perception (remember your cat’s eyes focusing to attack your feet). In addition, since this type of creature hunts at night, such an eye shape allows them to take advantage of even the dim light.
The horizontal eye shape of goats provides some advantages for them, but it causes them to have difficulty in finding the distance between them and an object.
The reason for this is that they do not have vertical pupils like cats and snakes. Since their depth perception is poor, they tend to avoid shadows and changes in colors on the ground.
The researchers say their next focus will be on the pupils of non-terrestrial animals.
The eyes of octopuses are also very similar to the eyes of goats. They can also look around from a wide angle. However, since these creatures are both herbivores and carnivores unlike goats, more research is needed on this subject.
Sources: 1, 2
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