Just as cats are known for their visual abilities, dogs are renowned for their keen sense of smell and their astute tracking skills. However, beyond the use of their noses, dogs also are able to hear things that are beyond the reach of human ears. For centuries, humans have counted on dogs to guard their homes, protect their livestock, and conduct search and rescue missions. To accomplish these great feats, we have relied heavily on a dog’s ability to hear and sense things that we cannot. Though hearing capabilities vary based on the age and breed of the dog, there is no doubt that canines have superior auditory skills.
How Does Hearing Work?
- Human ears: The physical structure of the human face is centered on vision being our primary receptor. Our ears are not able to move independently from our faces, as they are balanced on either side of our head, pointing one direction. Our brains capture sounds in our outer ear, which then travel in waves through the inner ear to the auditory nerve. Were we to lose hearing in one ear, it would not only affect the accuracy with which we could detect sound, but also would throw off our body’s equilibrium, since ears help humans determine depth perception and spatial distance between objects. While our ears are able to pick up the same low-decibel sounds as dogs can, they are not able to hear the higher frequencies that travel over a great distances the way dogs do.
- Dog ears: One of the primary differences between canine and human ears, is that dogs are able to position their ears to detect as much of the sound as possible. Dogs can move each ear independently from the other, so that one might determine the direction the sound is coming from as well as the distance, while the other can absorb a focused concentration of sound waves for an accurate analysis of what the sound might be.
Erect ears are more equipped to maximally detect noises, as the sound waves are captured by the far-reaching outer part of the ear. These waves then move through the middle ear, to the inner ear which contains the vestibule and semicircular canals. This part of the inner ear affects a dog’s equilibrium.
Like humans, dogs also rely on their hearing abilities to maintain physical balance. The small hairs located in the semicircular canals transmit currents to the brain. This helps the dog understand his surroundings and body position in regard to the ground/gravity. Tampering with ear size and positioning through the practice of plastic surgeries like ear docking and cropping, may impair the way the dog absorbs noise, which affects both his balance and the accuracy of sound perception.
Humans are able to detect sound waves ranging in frequencies between roughly 20 Hz -23,000 Hz. In comparison, dogs can hear frequencies ranging from 40 Hz – 60,000 Hz, reaching roughly 10.5 octaves of sound. This ability to hear high frequencies offers dogs a unique way to perceive the world. Humans have used tools to help train or call a missing dog that sound silent to us, but are audible to canine ears. These high-frequency whistles reach the ultrasonic range, and are a convenient way to communicate with your dog without noisily disrupting those around you.
Dog ears were designed to be sensitive, meaning that we might do things that cause our pups auditory pain, without realizing it. Next time you are vacuuming and your dog runs for the yard, bear in mind that he may be hearing unpleasant high-frequency sounds you do not!