Dear Dr. Warford, So What Exactly *Can* Dogs Hear?

You’ve probably noticed and heard, dogs have a more sensitive sense of hearing than we humans do. But what exactly can they hear? And why?

First, let’s look at the way they are built: we’ll start with the outside of the ears. We’ll cover the inner ear and common problems with it in another post- otherwise you’ll be reading for days!

Dogs begin to hear at about 3 weeks of age. In the list of senses, sound is second in sensitivity- and importance for survival- only to their sense of smell.

They have over 18 muscles controlling the movement of their ears- we humans have 6. This allows them to move in much more complicated, deliberate and focused ways than our human ears can.

They can rotate and tilt their ears, allowing them to get those sound waves more efficiently than we can.  Additionally (and very cool), their ears can move independently of each other, allowing them to locate and focus on sounds in different directions. It also helps that their ears tend to be larger and more erect than ours, again, allowing them to get those sound waves better than we can.

Have you ever seen your dog suddenly turn one ear in a different direction, even while their eyes are focused somewhere else, even when surrounded by other sounds? It is likely your dog has picked up a sound you may not even hear and is attempting to locate where it’s coming from.  It really shows their ability to screen noise, and filter out only what they think is new or important.

Most nerdy and doctor folks agree that dogs with heavy, floppy ears don’t hear as well as dogs with erect, upright ears, but they still have us beat by quite a bit.  A bigger concern with floppy eared dogs (not related necessarily to their hearing) is they are more likely to have ear infections due to the heavy ears hanging so close to their head.  Those big ears don’t allow air to get into the ear, giving gross little organisms a nice, warm place to grow. But again, I digress.

Now that we’ve covered what they are hearing *with*, let’s look at what *exactly* they hear. This might get a bit scientific and nerdy, but bear with me. It’ll be worth it.

First let’s talk about sound. Sound is a series of waves (technically: air disruptions) that reach our ears and are translated by our brains into the sounds we hear.

Sound is measured in different ways: including loudness and pitch. Pitch is measured by the frequency of wavelengths that are transmitted.  It is measured in Hertz (we use the acronym/shortened word: Hz).

One Hz means there’s one cycle/second. The lower the number, the lower the pitch, which will have more of a bass tone: like a fog-horn. The higher the number, the higher the pitch, such as a whistle.

This can get very complicated, but a simple explanation: Humans can generally hear a range of 20-20,000 Hz, and the human voice generally ranges from 1000-4000 Hz. Now get ready to be impressed: dogs can hear a range of 40-45,000 Hz, at least, and… likely more.

Some studies have indicated the high end could be closer to 75,000 for some breeds, especially those with large, erect ears.  But, what does that mean? It means that dogs can hear many sounds we can’t of higher pitch, which is why the dog whistle, which is silent to humans, can be heard by dogs. They can also pick up sounds we can’t in everyday life such as noises on the TV, ambulances from a distance, and even additional sounds from the vacuum cleaner, which might explain why they may react in ways that don’t seem to make sense to us. They may be hearing something we can’t!  To be honest, I think the vacuum cleaner is annoying enough. I can’t imagine hearing even more annoying sounds when it’s on.

Their anatomy and increased sensitivity to those same higher pitches, it is thought that dogs can hear sounds that are about 4 times further away than we can. This is important: go back and read again.  Four times further away!  Again, this is why dogs may react to ambulances before we even hear them and continue barking or howling even after we are no longer able to hear the siren. They are also better able to tell the small differences in sounds that we may not be able to.  But, keep in mind, all of this also means that some noises that are not terribly loud or annoying to us may be very annoying or even painful to our dogs:  a good rule of thumb is if it is a loud and painful noise to us, chances are it is *even more* uncomfortable for your dog.

Why do dogs have such sensitive hearing?

We doctor types seem to guess evolution.

We know that dogs rely (for the most part) on scent/smells and sound to track their food and/or prey.  It makes sense that their hearing would be better at telling the high pitch sounds their prey may send out: even from further away, and from many directions. If a dog had to rely on a human’s ability to hear, it wouldn’t last very long in the wild on a hunt for food.

So, the next time your dog is playing in the yard and suddenly stops and perks up its ears, remember: There’s a whole world out there that we just can’t appreciate.