A watchdog does a good job alerting a family if a stranger is approaching. Watchdog breeds include the chihuahua, pomeranian, airdale, Boston terrier, schipperke, miniature pinscher, and pekingese. These dogs will alert the family but will likely not attack. Good guarddogs include bullmastiff, German shepherd, giant schnauzer, akita, doberman, rottweiler, and Staffordshire terrier. The bullmastiff is especially good for families.