Wouldn't it be nice if our teeth replaced themselves whenever we needed a fresh set? No more drills. No more crowns. No more denture adhesives. That's what happens to sharks. In fact, some sharks replace their teeth every few weeks.
The teeth inside a shark's mouth are arranged in rows, like seats in a theater. While the outermost teeth do the work of grabbing, cutting, or crushing prey -- their function varies from species to species -- the inner rows of teeth mature. Then, when the shark sheds the worn outer teeth, the next row takes their place. It's a process that continues throughout the shark's life, with teeth being replaced more frequently the more actively the shark feeds.