Pupil functioning in dogs and cats
Pupil functioning in dogs and cats differs greatly from that of human pupils. Its characteristics, its form, and its capabilities do not cease to surprise the scientific community day after day.
The fascinating cat pupils
The predatory nature of cats is more related to the curious vertical shape of their pupils than you think. A study published in 2015 in the scientific journal Science Advances has analyzed the functioning of the pupils of predators that hunt at night, just as cats usually do.
According to this study, the vertically of the pupils of cats helps them calculate the exact distance to which their prey is found in environments where light is scarce.
Since the method of cat hunting is based on the surprise effect, this characteristic of their pupils is essential to calculate the height of the jump with which they will pounce on their totally unsuspecting prey.
Predators that use this method of hunting usually use two techniques to calculate the distance at exactly their prey:
- Using the method known as stereopsis, the brain compares the distance between two images that are projected on the retina of each eye. From the two-dimensional vision that our vision offers to the brain, it is able to combine the images to give rise to a single three-dimensional image.
- The following method allows animals to focus on a particular object by blurring those that are located behind and in front of it.
The vertically of the pupils of cats plays an essential role in their stereopsis process since the contours and depth of the objects are better appreciated in this type of pupils. Those of the dams, on the other hand, usually have a horizontal shape.
The canine pupils, more similar to ours than we think
Both anatomically and functionally, the pupils of dogs are very similar to those of humans: canine eyes are composed of a cornea, pupil, retina, cones, and sticks. Since they are located at the back of the head, they have a somewhat limited peripheral vision.
The pupil of the dogs reacts to the light in the same way as ours: once the cornea penetrates and reaches the pupil, it expands or contracts to control the amount of light entering the eye; then, allow it to pass to the retina so that the image is processed.
The main difference between his vision and ours is in the response of the retina to the stimuli. While the retina of humans has more cones than sticks, that of dogs works the opposite, which gives them a better night vision.
The fact that dogs have fewer cones than canes, unfortunately, affects their ability to distinguish colors. We have three different types of cones that allow us to absorb various light waves and, therefore, detect more colors. With their cones, dogs are not able to detect colors such as green, yellow or red.