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.
Instead, reward the behavior that is normal for your dog â bringing you a toy to play with or wagging his tail when he sees a leash, for example. If the depression persists and nothing perks up your dog, consult your vet. Just as with humans, some dogs get depressed as a result of a chemical imbalance or fluctuation. Your vet will be able to determine if the depression has a physical cause. If thatâs the case, they may discuss canine anti-depressants with you or recommend other courses of action to treat the depression.