Sharks Never Run Out of Teeth

A shark can go through thousands of teeth in its lifetime. It has never once been to a dentist.

Think about the last time you lost a tooth. You probably waited weeks for a new one to arrive. A shark doesn’t have that problem — not even close.

A shark’s mouth is built like a conveyor belt. There isn’t one row of teeth; there are several, stacked in a line running from the front of the jaw back into the gum. New teeth form at the back and inch forward over time, and by the time they reach the front row they’re lined up and ready for work.

When a front tooth breaks or falls out — which happens constantly, because shark teeth aren’t rooted into a jawbone the way ours are — the tooth behind it simply slides up to fill the gap. Some sharks replace a tooth every week or two.

Over a long life, that adds up. Estimates for busy species run into the tens of thousands of teeth, though nobody follows one shark around with a clipboard, so treat the biggest numbers as educated guesses rather than a count.

Right tooth for the job

Not every shark has the same teeth, because not every shark eats the same thing. Makos have long, slim, pointy teeth for grabbing fast, slippery fish. Nurse sharks have flat, crushing teeth for cracking shellfish. And a whale shark has thousands of tiny teeth it never chews with at all — it strains its food out of the water with its gills instead.

Professor Teeth, one of our sharks, insists this makes the shark mouth the most sensible design in the animal kingdom. He also insists you floss. He is a shark, so take the flossing advice loosely.

Did you know? Shark teeth aren’t fixed to the jaw like ours. They sit in flexible tissue, which is exactly why they pop out so easily — and why replacements are always on deck.