# What are these white structures in a sharks mouth? **URL:** \ **Category:** Factual Questions\ **Created:** [November 9, 2017, 4:48am UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102 "2017-11-09T04:48:23Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [November 9, 2017, 4:48am UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/1 "2017-11-09T04:48:23Z")
I’ve seen a few different videos of sharks with their mouths open wide. The side of the mouth has these vertical white structures running from top to bottom with dark spaces in between. They look kind of like bleached bone, which makes no sense. What are these things, and what are they for? When I first saw them in a basking shark video, I thought it was light shining through gill slits, but Here’s a good example of one lunging out of the water after some food: [SHARK FISHING - Go Inside The Mouth of a Sand Tiger Shark!!! - YouTube](https://youtu.be/tekBAIazdWw?t=6s) Here’s another one swimming peacefully through the water: [Basking Sharks Cornwall - YouTube](https://youtu.be/trDYQBuSVZY?t=10s) This video is a montage of wide open mouth shots: [The Basking Shark - YouTube](https://www.youtube.com/watch?v=8B0iI0OitAY) ---
**Author:** ![Sunny\_Daze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunny_daze/32/438_2.png) [@Sunny\_Daze](https://boards.straightdope.com/u/Sunny_Daze)\ **Post date:** [November 9, 2017, 5:03am UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/2 "2017-11-09T05:03:52Z")
I think those are gills. ---
**Author:** ![caligulathegod](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/caligulathegod/32/9685_2.png) [@caligulathegod](https://boards.straightdope.com/u/caligulathegod)\ **Post date:** [November 9, 2017, 5:14am UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/3 "2017-11-09T05:14:11Z")
Gill Rakers. > **[Gill raker](https://en.wikipedia.org/wiki/Gill_raker)** > > Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the gill used for gas exchange. Rakers are usually present in two rows, projecting from both the anterior and posterior side of each gill arch. Rakers are widely varied in number, spacing, and form. By preventing food particles from exiting the spaces between ... ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [November 9, 2017, 5:36am UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/4 "2017-11-09T05:36:19Z")
More specifically, they are the [gill (or branchial) arches](https://en.wikipedia.org/wiki/Branchial_arch) in all 3 vids, the rakers are only seen in the basking shark ones, tiger sharks don’t have them. ---
**Author:** ![Sunny\_Daze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunny_daze/32/438_2.png) [@Sunny\_Daze](https://boards.straightdope.com/u/Sunny_Daze)\ **Post date:** [November 9, 2017, 5:46am UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/5 "2017-11-09T05:46:56Z")
> [@MrDibble](#): > > More specifically, they are the [gill (or branchial) arches](https://en.wikipedia.org/wiki/Branchial_arch) in all 3 vids, the rakers are only seen in the basking shark ones, tiger sharks don’t have them. Thank you. I have learned something today. ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [November 10, 2017, 8:57pm UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/6 "2017-11-10T20:57:08Z")
Thanks, all. Why don’t these bony\* arches get infested with parasites (e.g. barnacles)? It seems like an ideal place for a filter-feeder to attach. There’s a steady flow of water (to feed the gills). You get scraps (and blood) every time the shark has a meal. Or to put it another way, why do fish and sharks have exposed bony\* structures in their mouth while in a mammals mouth the only exposed bone-like structures (i.e. teeth) are coated with a hardened material? \*Yes, I know it’s cartilage rather than bone, but I don’t know why cartilage would be more resistant than bone (to be fair, I know very little about biology beyond the basics I learned in grade school). ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [November 10, 2017, 9:34pm UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/7 "2017-11-10T21:34:39Z")
> [@dstarfire](#): > > Thanks, all. > > Why don’t these bony\* arches get infested with parasites They do. That’s what [cleaner wrasses](http://soloways.us/2013-01-15%20to%2030%20Big%20Island/2013-01-16/IMG_0510shark%20with%20remora%20and%20fishhook%20closeup_small.JPG) and other[service fish](https://en.wikipedia.org/wiki/Cleaner_fish) are for. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [November 10, 2017, 9:42pm UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/8 "2017-11-10T21:42:15Z")
> [@](#): > > What are these white structures in a sharks mouth? The last thing you see. ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [November 11, 2017, 7:50pm UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/9 "2017-11-11T19:50:06Z")
> [@Bosda\_Di\_Chi\_of\_Tricor](#): > > The last thing you see. Actually, it’s 5x more likely that [this](https://cdn.modernfarmer.com/wp-content/uploads/2013/06/cow-plague-hero.jpg) is the last thing you see ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [November 11, 2017, 7:56pm UTC](https://boards.straightdope.com/t/what-are-these-white-structures-in-a-sharks-mouth/801102/10 "2017-11-11T19:56:43Z")
> [@dstarfire](#): > > Actually, it’s 5x more likely that [this](https://cdn.modernfarmer.com/wp-content/uploads/2013/06/cow-plague-hero.jpg) is the last thing you see Yeah, that high-cholesterol food will kill ya.