Why Sharks Don't Have Bones

It's Shark Week and we've got some awesome shark facts for you. To start, did you know that sharks don't have bones? We'll tell you why in this bitingly good new episode of SciShow!
----------
Messages from our Subbable subscribers:

Maitrayee, you are an awesome astrophysicist!
- Matheen

Never lose your imagination!
- Michael Glibstrup
----------
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records: http://dftba.com/artist/52/SciShow
Or help support us by subscribing to our page on Subbable: https://subbable.com/scishow
----------
Looking for SciShow elsewhere on the internet?
Facebook:   / scishow  
Twitter:   / scishow  
Tumblr:   / scishow  
Thanks Tank Tumblr:   / thankstank  

Credits:
Hank Green - Executive Producer / Host / Writer
Blake De Pastino - Chief Editor
Caitlin Hofmeister - Producer
Stefan Chin - Graphics
Louey Winkler - Camera
Sarah Meismer - Editor
Michael Aranda - Script Supervisor

Sources:
The Mechanical Behavior of Shark Skin - http://www.ias.ac.in/jarch/jbiosci/22...
Importance of Cartilage - http://www.elasmo-research.org/educat...
FISH TO TETRAPODS - http://en.wikipedia.org/wiki/Evolutio...
Leydig’s Organ - http://en.wikipedia.org/wiki/Leydig%2...
Chondrychthyes - http://en.wikipedia.org/wiki/Chondric...
Osteichthyes - http://en.wikipedia.org/wiki/Osteicht...
Evolution of Fish - http://en.wikipedia.org/wiki/Evolutio...