Which animal has 750,000 teeth?

The Animal with 750,000 Teeth

Believe it or not, the creature holding the record for the most teeth isn’t a shark or a reptile — it’s a soft-bodied sea dweller known as the umbrella slug (Umbraculum umbraculum). This unassuming mollusk, found across the warm waters of the Indo-Pacific, quietly produces around 750,000 teeth over its decade-long life.

Unlike mammals, which grow a few sets of teeth at most, the umbrella slug continuously replaces its microscopic dental structures. These teeth aren’t used for chewing in the traditional sense. Instead, they line a specialized feeding organ called the radula — a sort of biological conveyor belt of tiny, chitinous spikes that scrape algae and other food from surfaces on the seafloor.

What’s even more remarkable is how efficiently the slug renews these teeth. As old ones wear down from constant use, new ones form rapidly at the back of the radula, moving forward like an assembly line. Over a lifespan of up to 10 years, this relentless replacement adds up to an astonishing total — roughly three times more than the next record-holders, certain species of eel and snail.

Despite its name, the umbrella slug isn’t a slug in the garden-variety sense. It’s actually a type of sea snail without an external shell, part of a diverse group of marine gastropods known for their vivid colors and unusual shapes. Its leathery body and low, shield-like profile give it a distinct, almost prehistoric look.

So, while the great white shark may get all the attention for its razor-sharp grin, it’s the humble umbrella slug — quietly grazing on coral and rock — that wins the tooth count by a landslide. Nature, as always, has a way of surprising us when we look a little closer.