Changes in Behavior Due to Health

• When you notice a change in your dog's behavior, it is advisable to visit a veterinarian as soon as possible. Many behaviors that are undesirable are caused by medical problems.
  
  

Changes To the Household Or Environment

• Have you recently moved or allowed someone new to enter the household? Even something as simple as the re-arranging of a living room can cause some dogs to act peculiar. If you've recently acquired a new pet or a roommate, it may take some time for your pooch to adjust.
  
  

Quality Time

• A dog's behavior may change if someone in the household gets a new job or if the dog is left alone for extended periods of time. The time they used to have lavished upon them no longer is there, and it may take a while for them to adjust. A pet-sitter may need to be hired.
  
  

Puppies - Growing Up

• If your dog is under 2 years of age, it still is going through stages to reach maturity. This can lead to a change in behavior every couple of months as it discovers something new. Some of these changes may be destructive (ie teething), but they are not always a cause for alarm.
  
  

Dogs Getting Older

• Observing changes in behavior in older dogs may be medical, or it may just be the dog's behavior changing. Eliminating medical causes, it may just be that your dog is not a puppy anymore and her personality has changed.
  
  

Odd Noises

• Check to make sure your smoke alarm batteries are functioning well and not too old. Some smoke detectors emit a high frequency noise when they are running low on battery that humans won't always notice, but dogs will.