As we all have seen, a feline's eyes shine in a beam of light at night. This is due to the tapetum luvidum, a mirror like membrane that lines most of the back of the retina. It reflects the light passing through the rods, then back through the rods a second time (the light passes through the opposite direction the second time). The tapetum reflects any light not absorbed on its first passage through the retina. As a result, the retina's light sensitive cells receive a second stimulation, increasing the eye's sensitivity to dim light (Warrant, 2004).  The combination of elliptical pupils and the Tapetum permit cats to see extremely well in near darkness.

Image courtesy of www.whataboutcats.com

In conclusion, a feline cannot see perfectly in the dark. It still needs light, albeit only a little, to see during the night. Even in some of the dimmest habitats on Earth, a nocturnal feline predator will use the moon light to the best of its advantage to help it see (Warrant, 2004). Due to the great anatomical advantage that a feline has (larger cornea, etc.) it can allow more light into the pupil. Thus more light can hit the rods.   These factors enable a feline to better use the limited light available compared to that of most diurnal mammals.

What is also interesting is that a feline is able to use the glow of its eyes to its advantage. It can use this glow to attract potential prey, yet it knows when to hide this glow at the appropriate time (like avoiding predators and amking sure not to scare the prey off). The anatomy of a nocturnal feline's eyes is just more proof that anatomy helps to predetermine behavior.

Questions or Comments? Please e-mail me at mirogers@davidson.edu