Humans have asked this question for a long time. Today, we are beginning to see it a little more clearly. We thought animals saw in black and white for a long time. Today, we know that this is not true. Not only is coloured vision widespread among them, but depending on the species, their eyesight can be much better than ours. Visual acuity is not the same for all species. It varies according to the environment in which they live, the speed with which they move, the prey they must hunt, and the predators they must escape.
That said, most species see the world in much less detail throughout the animal kingdom than humans.
The visual acuity of humans is similar to that of chimpanzees and other primates. Visual acuity defines the quality of vision. It is determined by the ability of a human or animal to discern two distinct points separated by the smallest possible distance.
Some birds of prey do better than humans. For example, the Australian triangle-tailed eagle can see more than twice the limit of human acuity. Eagles can see something as small as a rabbit while flying thousands of feet above the ground.
But except for a few eagles, vultures, and hawks, most birds see less than half the detail humans can. The same is valid for fish. The highest acuity in a fish is only about half of ours. Humans can see 4 to 7 times more detail than dogs and cats and 100 times more than a mouse or fruit fly.
In summary, the human eye is an excellent generalist that adapts to virtually any terrestrial situation. It is sensitive to sharpness, resolution, contrast and motion and is suitable for near, far and night vision. This versatility is a quality of its own. The downside is that it does not perform in a particular area, as with animals.
