To say that dogs have better hearing than people is as much an understatement as saying that people are bigger than mice. Mother Nature gave dogs auditory capabilities that would make the world an endless cacophony for people if they suddenly could hear so well. Dogs do, however, lose their hearing for the same reasons people do.
Born Deaf, But Not for Long
The only time people have the edge over dogs when it comes to hearing is at birth. While humans can hear from the get-go, puppies are born deaf and blind and must interpret their worlds entirely by smell. Most dogs won't get their hearing until about three weeks after they are born. By the time dogs fully develop their auditory sense, they can hear sounds significantly farther away than people can. What a person could hear at 100 feet, for example, a dog could hear at a quarter-mile.
A dog's ears are built wide and deep to help them detect sound waves more clearly than people. They also have at least three times the ear muscles of a person. Dogs have 18 or more muscles in their ears, which allow them to move their ears more freely toward different sounds. People, by comparison, have only six muscles in their ears and can, at most, wiggle them as a party trick.
Because of the construction and sensitivity of their ears, dogs can hear much higher frequencies than people. However, people generally can hear slightly lower frequencies than most dogs. Whereas people can detect sounds ranging from 64 to 23,000 Hertz, dogs can detect sounds ranging from 67 to 45,000 Hertz. This is typically why dogs become agitated at such sounds as vacuum cleaner motors, which to them sound like a shrill, high-pitched whine.
Despite those incredible ears, dogs, like people often lose much of their hearing as they age. Other causes of deafness for humans and dogs typically include degenerative nerve damage, tumors or cancers centered in the ears, viral or other infectious diseases, blunt trauma and reactions to toxins or drugs, such as antibiotics or chemotherapy medications. Other risk factors include chronic inflammation of the ears and heredity. Roughly 30 breeds of dog are especially susceptible to deafness.