Because All vertebrates share the same basic eye structure: a pupil that dilates or constricts to control how much light enters the eye, a lens to focus the image onto a light-sensitive retina, and nerves that relay the information to the brain. Yet humans flounder with the departure of daylight, while many animals are able to forage and hunt by night.
1 5 1
Some animals can't see at night time because they have less 'rods'(the light sensing cell in the eye).
example: humans