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.
One of the most common causes of a fear or phobia in dogs is a lack of early socialization. Dogs go through a critical period of development when they are between the ages of 8 and 16 weeks. Dogs that aren't exposed to new things during this period may become fearful of new things later in life.