Dogs that are dying of old age exhibit symptoms such as impaired movement, reclusion, restlessness, sadness, lack of interest and incontinence. These symptoms lead to an inability to feed or hydrate properly, which might cause death in older dogs. Other dogs may simply pass away in their sleep.
Overall decline in functionality is expected with aging dogs, and older dogs often experience a loss in one or more senses. Memory and the ability to learn can be impaired due to senility, and a dog may no longer respond to prior training as well as before. Strange behavior can result from the dog feeling the decline associated with aging. Irritation, lack of grooming, confusion and even aggressiveness are possible behaviors.
Dogs near death often search for hiding spaces where they can pass away in relative peace. This is due to a dog's instinct to protect itself from other animals that might take advantage of the dog in its weakened state. A responsible owner should seek veterinary care if the dog is in obvious chronic pain or unable to move or sit. Sometimes these problems can be treated with pain management and other quality-of-life considerations, but in other cases euthanasia may be the best option.