Research overview: nocturnal evolution and reduced color vision in carnivores

Most mammals, including cats, have less elaborate color vision than birds, reptiles, or many fish, a pattern often traced to a nocturnal phase early in mammalian evolution. This overview surveys the hypothesis that ancestral mammals lost cone diversity while specializing for dim-light vision, leaving descendants such as cats with dichromatic color systems. The cat fits this story well: a crepuscular predator whose retina favors rods, sensitivity, and motion detection over rich color. The survey reviews comparative evidence across carnivores and the broader mammalian radiation, including the later re-elaboration of trichromacy in some primates. Placing feline color vision in this evolutionary frame explains why the cat sees a limited palette not as a defect but as an inherited consequence of ancestors that prospered in the dark, where color was less useful than catching faint light.