Alsatians, Dobermans, Rottweiler and other large powerful breeds have been employed to guard private property. Other breeds have also been used by the police, military and customs to track illegal drugs and explosives as well as rescue trapped or injured people (Swabe).
Similarly, canines have been increasingly used to assist disabled humans. With this, they are called "guide dogs." This paper focuses on "hearing dogs" or guide dogs that aid the deaf. It provides an overview as to how these special canines are trained in order to help their hearing-impaired masters. Furthermore, this paper cites some amazing true-to-life encounters of dog-owners and their hearing dogs.
Hearing dogs are specially trained to call the attention of their hearing-impaired owners to various sounds which they recognize. They are taught to identify two types of sounds, these are danger sounds and alerting sounds ("Border Telegraph Newsroom"). Danger sounds include fire alarms and sirens. When the smoke alarm sounds, the hearing dog is trained to take his/her owner to safety. Since the deaf may not be able to hear the siren of an emergency vehicle while he/she is driving, it is critical for the hearing dog to let the owner know when one is approaching. ("Florida Dog Guides")
On the other hand, alerting sounds include everyday noises such as ringing telephone or doorbell, someone ...