Any breed of dog can potentially produce a good hearing dog. However, most hearing dogs are mixed-breed dogs selected for higher than average energy level and a weight of 30 to 40 pounds.
A "hearing ear dog," more commonly referred to as a "hearing dog" is specially trained to assist people who are deaf by signaling them of the presence of common sounds that require attention. Each dog is individually trained to their specific handler's needs. For example, if the handler has an infant, she would want her dog trained to alert her when the baby cries.
Hearing dogs are commonly trained to respond to the following sounds:
a doorbell or knock on a door
a telephone ringing
the sound of the handler's name being spoken
an oven or microwave timer
Upon hearing a sound the dog is trained to recognize as important, the hearing dog signals his handler, usually by poking or pawing at their leg, then either turns to look in the direction of the noise, or runs back and forth between the source of the noise and the handler to indicate where the noise is.