Chinese folklore includes a rhyme about the pupil of a cat’s eye expanding three times a day: “Tiger, rabbit, snake, rooster like a seed; Dragon, snake, horse, goat like a thread; Rat, ox, dog, pig like a full moon”. What gives cats this remarkable ability?
Understanding the Unique Changes in a Cat’s Eyes Throughout the Day
It turns out that the pupils of cats are very large, and the ability of the circular muscles in their pupils to contract is quite strong. In humans, if we stare at the sun, our pupils will constrict. However, we can only shrink them to a certain extent; otherwise, we will start to experience eye discomfort. On the other hand, if we gaze into a dark place for too long, we may feel dizzy.
A cat’s pupil can constrict to a very small size to adapt to bright light. (Photo: users)
Cats, however, can adapt very well under varying light conditions. In bright daylight, a cat’s pupil can shrink to an extremely small size, resembling a thread. At night, when it is pitch dark, the pupil can widen to the size of a full moon. During the early morning or twilight, the pupil takes on the shape of a seed.
Thus, a cat’s pupil has a much greater capacity for contraction compared to human pupils, making their reaction to light more sensitive than ours. Therefore, regardless of whether the light is too strong or too weak, cats can still see objects clearly.
