Whether dogs can hear lower frequencies than humans is an important question than can help us better understand our canine companions. In order to better understand the frequencies that dogs can hear, it helps to get get better acquainted with a dog's hearing capabilities and comparing their hearing to a human's. Veterinarian Dr. Ivana discusses how dogs hear, describing into detail the frequencies dogs can detect so to determine whether some sounds can turn annoying to a dog's ears.
Can Dogs Hear Lower Frequencies than Humans?
So what sounds ranges and frequencies can dogs hear? We know that dogs are superior to us when it comes to sense of smell, but what about the sense of hearing? Well, sadly for us, dogs are superior at this too. To better appreciate our dog's sense of hearing, it helps taking a closer look into how our dog's ears work. So let's take a little lesson on the anatomy of the dog's ear.
The dog’s ear has three distinct parts and each part has its own structures. It is composed by 1) the outer ear, which consists of the pinna, the external ear canal and the ear drum, 2) the middle ear, which includes the tympanic cavity which contains three tiny bones also known as auditory ossicles (malleus, stapes and incus) and 3) the inner ear, which consists of the vestibular apparatus and the cochlea (which houses the organ of Corti).
How do dogs hear? When a dog hears a sound, the ear flaps capture it and channel the vibrations down the ear canal to the ear drum, which vibrates in turn and conducts the sound along three tiny bones (the auditory ossicles) to the oval window membrane. From here, the vibrations are transmitted to the organ of Corti, which translates them into coded nerve impulses and sends them via the auditory nerve to the brain.
A dogs hearing range is superior to ours. In fact, the dog’s hearing range is twice as wide as the human’s hearing range. To be more accurate, according to Louisiana State University, humans can hear sounds between 64-23.00Hz while dogs can detect sounds between 67-45.000Hz.
Although capable of hearing higher frequencies, dogs do not have the widest hearing range. Whales and bats can catch sounds up to 110.000Hz, although they are not very good at detecting lower sound frequencies. Simply put, dogs are not the leader when it comes to hearing wide ranges, but they are definitely much better than us!
Why Do Dogs Hear Better Than Humans?
The next question may be now: why do dogs have superior hearing capabilities than humans? It is the dog’s ear anatomy that gives an advantage at hearing sounds. In a nutshell, dogs have particularly large external ears. Additionally, most dog breeds can adjust the ears’ shape and direct them towards the sound source. This ensures better transmission of the sound to the ear drum.
Last but not least, the cochlea (located in the inner ear) has more turns – the dog’s cochlea has 3 ¼ turns while the human’s cochlea has only 2 ½ turns. Having more turns means providing more space for sensory sound cells.
Why can dogs hear sounds that are inaudible to us though? Is there some evolutionary advantage? The answer is yes. This is in part due to the "wolf" in dogs, or better said, their predatory heritage.
Dogs are therefore capable of detecting the high-pitched sounds made by small rodents such as mice and rats-animals that are part of a wolf’s summer diet. On of of this, dogs can also detect the high-frequency sounds emitted by bats.
Vampire bats, in particular, are a problem in Central and South America because they feed on cattle’s blood, but they seldom feed on dog blood – and that's because dogs, unlike cattle, can hear them coming. This has opened the path to a new type of employment for dogs: detecting bat sonar to protect herds of cattle.
"A new job proposed for dogs is standing guard on cattle herds and listening for bat sonar. When they detect bats, the dogs could then sound a warning to start the cattle moving, which would save many animals from injury and infection."~Stanley Coren, How Dogs Think, Understanding the Canine Mind
What Sounds Frequencies Are Dogs More Comfortable With?
Although dogs can hear sounds with frequencies ranging between 67 and 45.000Hz, they do not enjoy exploiting their entire hearing range. In fact, dogs prefer hearing sounds that are closer to the human range – up until 23.000Hz.
Sounds between 23.000 and 25.000 Hz are also acceptable. In fact, dogs find these ranges quite appealing because they are different from the familiar range of sounds frequently present in the human environment. Dog food manufacturers often experiment by adding sounds in these frequencies to their adverts – their goal is attracting dogs to their commercials.
However, frequencies above 25.000Hz, based on the circumstances can become irritating for dogs. We say based on the circumstances because the frequency is not the only factor triggering discomfort – the volume is also quite important. Simply put, frequency plus volume equals hearing discomfort. The higher and louder the sound is, the more likely it is to cause irritation and discomfort. When faced with loud and high-frequency sounds dogs respond by whining, whimpering or simply running away.
Humans turned that tendency into their own advantage. Namely, today, high-frequency sounds are used in dog training. This is because such sounds tend to distract, startle, confuse and irritate dogs without causing permanent hearing damage. Generally speaking, high-frequency sounds can be used to call dogs, distract them from misbehaving and deter them from approaching.
Equipped with such good ears, many dog owners may wonder whether dogs may have a sixth sense. No, dogs do not have a sixth sense. However, they have incredible hearing sense. That is why they are good at predicting earthquakes or announcing someone’s arrival before ringing the bell or even parking the car. On the down side, this same capability makes dogs scared from everyday tools such as vacuum cleaners, lawn-mowers and power drills. Dogs can hear these tools’ high-pitched noises that are inaudible to us. Plus, the tools’ noises that are audible for us are way too loud for dogs.
How do Veterinarians Test a Dog's Hearing?
The only way to objectively asses the dog’s hearing abilities is through the so-called BAER (brain-stem auditory evoked response) test. The test works by registering electrical activity in the cochlea and recording the auditory pathways in the brain. Simply explained, the test is conducted by placing electrodes on the dog’s scalp and earphones in the ears. Different sounds are played through the earphones and if the brain responds to the sound by showing electrical activity, the machine registers the response and determines that the dog heard the sound.
The BAER test is painless, relatively easy to perform on relaxed dogs and does not require much time. Once the machine registers the responses, a vet who has training in this technique will interpret the results.
Did you know? Ivan Pavlov discovered that dogs can distinguish between two notes that differ by only one-eighth of a tone. Whether they enjoy or dislike music is another matter. There are reports about dogs attacking their owners or displaying dislike when certain music is turned on.
About the Author
Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia. She currently practices as a veterinarian in Bitola and is completing her postgraduate studies in the Pathology of Domestic Carnivores at the Faculty of Veterinary Medicine in Zagreb, Croatia.Ivana’s research has been published in international journals, and she regularly attends international veterinary conferences.