Dogs’ hearing

Dogs’ hearing

We have all noticed that when we arrive home by car that our dogs are sitting at the gate ready to welcome their leaders. That is because dogs have a keen sense of hearing many times better than ours. They can hear and recognize the engine sounds of our cars when we are still a few blocks from home. How many times has your dog started barking at seemingly nothing, leaving you curious about what they are hearing that you are not?

They can hear twice as many frequencies as humans and also hear sounds four times further away.

But what does that actually mean?

Dogs can hear a wider range of frequencies, measured in hertz (Hz). Babies can hear up to 20,000 Hz while dogs can hear up to 35,000 Hz. This means that they are able to hear much higher pitches of sound than humans. That is why dog whistles that are silent to human ears emit sounds that are too high for us to hear but dogs can hear them quite easily. This also means that they can be agitated and discomforted by sounds emitted by electronics that we can’t hear. Dogs also can hear sounds at lower decibels than humans, meaning they can hear softer sounds than we do. This also means that loud sounds are louder to dogs and can explain why dogs are often scared or agitated during thunderstorms or fireworks events.

But how do we know that?

We know that humans can hear because they can tell us, but how do we know what dogs can hear. In earlier studies dogs had to be trained to press a lever under a speaker when they heard a sound. Today a dog’s hearing abilities can be tested without the dog having to do a thing. The Brainstem Auditory Evoked Response (BAER) hearing test places electrodes on a dogs head and earphones in his ears. Sounds are played through the earphones and if the brain shows electrical activity, the dog is considered to have heard the sound. The test doesn’t hurt the dog and only takes a short amount of time.

Just like humans, dogs can lose their hearing with age or from factors such as a severe ear infection. The BAER test is also used to determine the level of hearing loss. Most dogs adapt well when their ears fail and one can continue to communicate using hand signals and body language. The ability to detect high-pitched sounds is usually the last to go, so louder, high-frequency sounds like a whistle, may work when your dog can no longer hear your voice.

But are they listening to us?

How many times have you called your dog to come inside from barking at the gate, only to find it has fallen on deaf ears? You know that he has simply ignored you. Just like humans, dogs often practice selective hearing, especially when they don’t want to do something. Dogs have the ability to hear and also to filter out sounds e.g. when playing back a recording you made you may hear a back ground noise (e.g. car hooting) that you had filtered out while making the recording.

Don’t call your dog while he is scratching himself, sniffing another dog or smelling an interesting spot on the ground. Call as soon he stops doing it. At the play park are unlikely to respond when called to go home. Instead, call him to you 5 minutes after your arrival at the park, praise and reward him for coming to you and tell him to go and play again. Repeat this ritual a few times and soon he learns to return whenever you call.

At the club I regularly ask the handlers to see if they can get their dogs to lie down without speaking to them. Invariably they all succeed by bending down and pointing to the ground. I then ask them to turn their backs on their dogs, now sitting behind them, fold their arms in front of them, look straight ahead and tell their dogs to lie down. This always ends in a fun exercise because they will tell their dogs to “Down” repeatedly with many body contortions as they try to get them to obey. Usually only one of the dogs will obey. These handlers all were under the impression that their dog knew the “Down” command, but because they continued to point to the ground when giving the command, their dogs obeyed their body signals and not their voices.

Dogs pay more attention to gestures than they do to spoken commands, and they get confused when our visual and auditory signals do not align. Researchers have also found that dogs listen not only for certain words but to the tone of voice and intonation as a signal than to the actual word spoken. During training for Canine Good Citizen Gold test, one contestant repeatedly told her dog to….“Go to bed” with little success. When told to change the tone of her instruction from a “request” to a command, he immediately ran to his bed.

Using MRI techniques, researches at a dog lab in Hungary scanned the brains of dogs as they listened to recordings of their trainers’ voices. The trainers used praise words such as “well done” and neutral words such as “however” and spoke to them in a high-pitched “good boy” voice as well as a neutral voice. When praise words were spoken with a praising intonation, the reward centre of the brain was activated, but not when praise words were spoken with a neutral intonation.

Successful dog training therefore depends to a very large extent on the handler’s ability to get and maintain a dog’s attention in the way he can use his voice to communicate and praise his dog. After all, dog training is about voice control and leash control should only be used as a “correction” (stop doing what you are doing) or in an emergency. Also read: “Voice control and No.”

How dogs use their ears to hear

One of the reasons dogs can hear so well – better than humans – and at  high pitch sounds is because they have 18 muscles in their ears, all of which work together and allow them to hear sounds coming from all different directions. Humans only have 6 muscles in their ears and most of us can’t move our ears even a little bit. Dogs have the ability to tilt and rotate their ears in order to pick up certain sounds and “funnel” them into the inner ear more efficiently. The canine ear canal is considerably longer than in humans. Dogs with perky ears such as German Shepherds and Terriers have better hearing than breeds with floppy ears.

Very little systematic research has been done on how dogs use sound and hearing in their interactions with people and other dogs. We know that dogs make a lot of different sounds such as growls, barks, whines, whimpers, howls and pants, but scientists don’t fully understand how they use them in interacting with others. For instance, dogs bark often but we still don’t know much about what they are trying to say with their barks.

More Facts about Canine Ears and Hearing

1. A dog’s level of attention can be determined by watching his ears. Erect ears facing forward indicate that he is engaged, and slightly pulled-back ears signal that he is feeling friendly while ears folded tightly back against the head suggests a fearful or timid reaction.

1. Dogs’ ears move independently of one another.
2. Even during the quiet hours of the night – the world is a noisy place for dogs, who can hear the inner workings of digital alarm clocks and the bodily vibrations of termites in the walls. However, thinking is that they can possibly filter out most general noise.
3. A dog’s ear canal is L-shaped: vertical towards the jaw, then makes an almost 90 degree turn towards the eardrum.  This makes examination difficult and is the reason why dogs can have a variety of ear ailments, including parasites and yeast infections.

1. Cats can hear even higher frequency sounds than dogs.
2. University of Cincinnati researcher Pete Scheifele is developing a hearing aid that will help dogs with acquired hearing loss.