"Cat eyes" refer to the unique appearance of a cat's pupils, which can change shape depending on the light. In bright light, a cat's pupils constrict to narrow slits, helping to reduce glare and protect their sensitive eyes. In low light, the pupils dilate to allow more light in, enhancing their night vision. This ability is crucial for their hunting instincts, as cats are crepuscular animals, most active during dawn and dusk. The reflective layer behind a cat's retina, known as the tapetum lucidum, contributes to their night vision. This layer reflects light that passes through the retina, giving cats a distinctive glow in low-light conditions. This adaptation allows them to see in near darkness, making them effective hunters.