When light shines into the eye of an animal having a "tapetum lucidum", the pupil apiridescence, the color varies slightly with the angle at which it is seen and the color of the source light.
When light shines into the eye of an animal having a "tapetum lucidum", the pupil appears to glow. However, since eyeshine leads to iridescence, the color varies slightly with the angle at which it is seen and the color of the source light.