Why do cat's have vertical pupils?

"Vertical, or slit, pupils have the ability to dilate or constrict to a wide range of sizes, therefore determining how much light can enter the eye," says Dr. Gabrielle Fadl, DVM, veterinarian at Bond Vet. "The primary purpose of this in domestic cats is to allow vision in bright day light as well as dim night light."

Vertical, or slit, pupils have the ability to dilate or constrict to a wide range of sizes, therefore determining how much light can enter the eye," says Dr. Gabrielle Fadl, DVM, veterinarian at Bond Vet. "The primary purpose of this in domestic cats is to allow vision in bright day light as well as dim night light."