Introduction

If you've ever watched a nature documentary featuring sharks, you've seen the quintessential shot of a shark breaching the surface of the water, jaws gaping wide with row after threatening row of razor edged teeth to engulf some prey.

A white shark (Carcharodon carcharias) feeding at the surface by Fallows, Gallagher, & Hammerschlag 2013 and licensed under CC BY 2.5.

If you thought it looked like the shark was shooting its jaws out of its skull, you weren't imagining things! Many sharks have the ability to protrude their upper and lower jaws forward as they are opening their mouth, allowing them to "reach" their jaws toward their prey to take a bite (Wilga & Motta 1998). How is it possible for sharks to do this? In this module, you will figure out for yourself by building the skeleton of a shark skull, using your model spiny dogfish shark.