One of the facts of life for humans is the replacement of baby teeth with permanent adult teeth. Whether pulled out prematurely, wiggled loose by eager hands or naturally falling out unexpectedly, this occasion marks an important milestone in the maturation process that is shared amongst all vertebrates in some form.  Imagine, though, losing and replacing a tooth every single day. 

Contrary to what popular media portrays, we actually don’t know much about what sharks eat. Even less is known about how they digest their food, and the role they play in the larger ocean ecosystem. For more than a century, researchers have relied on flat sketches of sharks’ digestive systems to discern how they function — and how what they eat and excrete impacts other species in the ocean.