Best Answer: The pupil size limits the the amount of light that enters the eye. There are also day-time photoreceptors, the cones, which occur with three kinds of photo-sensitive pigments, for red, yellow-green, and blue.
Those âdevotedâ dogs lying on their mastersâ graves? Theyâre depressed. âMany dogs are simply depressed for their whole lives because theyâre deprived of the normal amount of attention, exercise, and stimulation they need from day one. These humans wonât know they have a problem and wonât want the dog any livelier as that wouldnât fit in with their lifestyle,â says Tamara.
The number one reason dogs are anxious, aggressive, and unhappy is because they lack adequate exercise. - Steven Brown DVM  The importance of the dog walk has seemed to slip away in this country. Proper exercise in dogs is the single most important preventative measure one can take for the longevity of their pet, as well as for their mental and emotional well being. The number one reason dogs are anxious, aggressive, and unhappy is because they lack adequate exercise..