There's no question that dogs do some strange things. Most of them, though questionable or even gross to us humans -- coprophagia and sniffing butts come readily to mind -- are perfectly natural for canines. However, if your dog stares into a corner or at a wall, it can be cause for concern, particularly if she's elderly. Such staring is a hallmark symptom of canine cognitive dysfunction. Make an appointment with your vet.
Before you get too upset, there's an inconvenient but fairly benign cause that may explain your dog's staring into the corner. You might have mice or other creatures residing in your walls. Your dog can hear and smell them much better than you can, and the distracting sounds or scents may hold her interest for extended periods. If she whines, growls, sniffs, scratches at or otherwise draws attention to the area, there's a good chance an infestation explains your dog's odd behavior.
Like people, most dogs experience some degree of decline as they age. They become more fatigued and less active, less motivated to pursue typical doggy interests and less alert and aware of their surroundings. Their memories and senses often fade a bit, too. Also, arthritic pets may feel aches, discomfort or outright pain when they move around, so they become more inclined to just stay put. Your dog might be staring off simply because it's how she feels like passing some time.
Canine Cognitive Dysfunction
Unfortunately, the effects of aging aren't always so innocent, and a behavior like staring into a corner often points to cognitive dysfunction in an older dog. This is basically the canine equivalent of dementia or Alzheimer's disease. Other common symptoms include social withdrawal, changes to sleep patterns, appetite changes, inappropriate soiling, pacing, circling, aimless wandering, seeming lost, difficulty remembering where things are or known commands, trouble navigating around furniture or obstacles, non-responsiveness, not recognizing family members or a name and irritability.
What to Do
If you've decided rodents have taken up residence in your wall, place a call to your friendly neighborhood pest control business. Otherwise, it's time to meet with your vet. He might want to rule out other medical conditions that could explain your dog's staring into the corner, especially if she's not in her senior years. Brain tumors and other neurological conditions may be suspect. He'll want a thorough accounting of the staring and any other new behaviors or possible symptoms you've observed. If aging or cognitive dysfunction are a concern, he'll help you devise a plan to make your pet as comfortable as possible and to facilitate aspects of daily life that are becoming more difficult for your dog.