If you have a dog in your life, you've likely thought that their sense of hearing seems like a superpower. You might have noticed that your dog is always at the door waiting to greet you even though they couldn't see you walk up. Maybe you've blown a dog whistle and watched your dog whip around to stare at you, but you couldn't hear a thing. But just how good are dogs' hearing abilities?
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A dog’s ears
Floppy ears, sticky-uppy ears, one up and one down – humans don't discriminate when it comes to the cute factor of dogs' ears. Most dog owners can tell you that the way a pup moves their ears can be very expressive, but these movements actually serve a purpose beyond being adorable. Dog ears are very mobile, and their earflaps (called pinna) alone contain 18 different muscles. These muscles are responsible for a dog's ability to raise, lower, and rotate its ears in order to pick up sounds more easily. Dogs have a longer ear canal than humans, and muscles within the canal allow a dog to finely-tune its positioning in order to accurately pinpoint sounds.
How well can dogs hear?
In order to understand just how well dogs can hear, it's helpful to examine the science of sound. Sound travels in waves and is measured by both frequency and amplitude. Frequency, measured in hertz (Hz), refers to the number of sound vibrations occurring in one second. Amplitude, measured in decibels (dB), measures how forceful a sound wave is. An easy way to discern these is to remember that frequency measures the pitch of a sound (how high or low it is), while amplitude measures how loud a sound is.
Human ears can detect frequencies between about 20 hertz (low) and 20,000 hertz (high), while dogs can detect frequencies from about 65 hertz and up to 60,000 hertz. This much wider frequency range gives dogs the abilities to hear high-pitched sounds undetectable to human ears.
Dogs can also hear much softer sounds than humans can. At zero decibels (the "threshold of hearing"), sound can just barely be detected by a human. While dogs don't hear lower frequencies as distinctly as we do, at high frequencies their decibel sensitivity is unmatched. At frequencies between 3,000 and 12,000 hertz, dogs can detect sounds as low as -5 decibels. Sounds below 20 decibels are referred to as infrasound and are below the range of humans' hearing abilities. Sources of infrasound include earthquakes and storms, as well as sounds made by bats and insects. Dogs can detect these noises that go unnoticed by humans.
Why do dogs need sensitive hearing?
Dogs evolved from wolf ancestors which needed to be efficient hunters in order to survive. Their ability to hear high-frequency sounds emitted by small rodents helped them locate prey. Dogs have maintained this stellar sense of hearing throughout their evolution and domestication.
Though dogs can hear infrasound produced by different animals, like most mammals they do not communicate using these low-range frequencies. In fact, most mammals are able to hear sounds well above the frequencies they are capable of producing. Dogs have evolved this precise sense of hearing in order to locate where sounds are coming from, a technique known as binaural spectral-difference cueing. This helps dogs to compare the frequency range of a sound as it arrives in each ear. Depending on which direction a sound is coming from, one ear may be "overshadowed" by the head and only some frequencies will be absorbed (higher frequencies are absorbed more than lower ones). The shape of a dog's head determines how well they are able to discern these spectral differences between frequencies.
Are some sounds painful to dogs?
If you share your home with a dog, you've probably noticed them becoming distressed by fireworks or rushing to the other room when you turn on the vacuum. With their ultra-sensitive hearing, some sounds can indeed be physically painful to dogs. The motor of a vacuum emits high-pitched sounds that humans can't hear, and this is likely the reason for the canine crusade against this household appliance. The loud booms of fireworks, thunder, and gunfire can also hurt a dog's ears. High-pitched frequencies like sirens can cause discomfort, as can very loud music in an enclosed space like a room or car.
If your dog is experiencing discomfort from a certain sound, you may notice them trembling, panting, whining, barking, or pacing. If possible, identify what is causing the sound and remove the source, or move the dog to a quieter area.
Hearing loss in dogs
Like humans, dogs can also become deaf or hard of hearing due to infection or aging. Dogs experiencing hearing loss may have an initial period of sound sensitivity or confusion, but they generally adjust well and lead happy lives. You can teach visual cues to your dog along with verbal commands, which not only makes them more attentive to training but can help with communication if they do lose their hearing later in life.
Dogs have evolved an incredible sense of hearing that helps them detect sounds both below and far above the frequency that humans can. This aided their ancestors in hunting prey and recognizing threats. Their precise hearing ability makes them sensitive to particular frequencies and amplitudes and can seem like a sixth sense.