# What are the structures in dog's ears for? **URL:** \ **Category:** Factual Questions\ **Created:** [April 20, 2003, 3:36pm UTC](https://boards.straightdope.com/t/what-are-the-structures-in-dogs-ears-for/169858 "2003-04-20T15:36:54Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![BlueMoonofKentucky](https://avatars.discourse-cdn.com/v4/letter/b/8dc957/32.png) [@BlueMoonofKentucky](https://boards.straightdope.com/u/BlueMoonofKentucky)\ **Post date:** [April 20, 2003, 3:36pm UTC](https://boards.straightdope.com/t/what-are-the-structures-in-dogs-ears-for/169858/1 "2003-04-20T15:36:54Z")
Of the many piddly things that keep me awake at night, I’ve been pondering the “structures” in my dog’s ears. Specifically, I’m wondering about those fleshy little protuberances just inside the ear canal itself. It seems that all dogs have the same structures, with the same shapes in relatively the same places, so what are they for? Why don’t we humans have any such shapes beyond our pinnas? Are they an organic canine waveguide? Do they serve to attenuate certain frequencies? Do they assist in pinpointing the location of a heard sound by some sort of built in time delay? What’s the dope on my Chihuahua’s ears, no my friends, not the long pointy parts, or the bony workings around the cochlea, but the stuff between? I’ve asked him, but get little more than a Zen like lick as an answer. Thanks BMoK ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [April 20, 2003, 7:32pm UTC](https://boards.straightdope.com/t/what-are-the-structures-in-dogs-ears-for/169858/2 "2003-04-20T19:32:20Z")
Just a WAG (and sorry for the unintentional pun): I remember seeing those structures in the ear when my family used to own dogs. Perhaps they are a part of the cartilege plate, there to protect the structure of the ear canal itself? As dogs in the main (except perhaps for those with the floppiest ears) have excellent muscles controlling the pinnas to direct sound into the canal, I can’t see why they’d need the extra folds and tucks within for extra hearing accuracy. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [April 20, 2003, 9:58pm UTC](https://boards.straightdope.com/t/what-are-the-structures-in-dogs-ears-for/169858/3 "2003-04-20T21:58:30Z")
Like the wrinkles in human ears, they assist in locating where a sound is coming from. As I wrote a few weeks ago: > [@](#): > > The shape of our outer ears, or pinnae came about for localizing sounds. The combined effects of the ridges plus the rest of the head, shoulders and upper torso cause scattering, delay and acoustic filtering of incoming sounds. Collectively, this is called Head-Related Transfer Funcion, or HRT. > > As a side note, HRT has been fairly well conceptualized in mathematical formulas, which can then be translated into acoustic filters. These filters (signal processing) are what’s behind simulated/enhanced surround modes on many home theater systems. > > If our ears were simply holes in the sides of our heads, we would be able to determine left-right location, but it would be more of a fully left/right, rather than somewhere between level of localization. ---
**Author:** ![BlueMoonofKentucky](https://avatars.discourse-cdn.com/v4/letter/b/8dc957/32.png) [@BlueMoonofKentucky](https://boards.straightdope.com/u/BlueMoonofKentucky)\ **Post date:** [April 20, 2003, 11:20pm UTC](https://boards.straightdope.com/t/what-are-the-structures-in-dogs-ears-for/169858/4 "2003-04-20T23:20:50Z")
Thanks, \*\*gotpasswords \*\* I had figured they were either there to help poochie locate the source of sounds, or they were there to attenuate sounds that may echo or resonate within the ear itself. I’m continually amazed at what this little dog can hear: I hear nothing, and he’s aiming each of those huge pinnae independantly at a myriad o’ stuff. It’s not hard to imagine the dog sittting there like a sonar array, drawing mental pictures of the aural world around him. Those are rather odd shapes, it amazes me to think of the evolutionary forces that must have sculpted them… Greatly appreciated.