Deep Look

(Narrator) What is this creature takinga bite out of your toe?

(Beachgoer) Ow!

(Narrator) And ruining your day at the beach?

Some people call them sand piranhas.

Scientific name: Excirolana chiltoni.

These tiny crustaceans are on the prowl forprotein, and they dont care where they get it.

From dead animals like this pipefish that washed up on the shore, to beachgoers flesh in this case, your ankle.

One bite feels like the nick of arazor blade sharp and then stinging.

But with enough time, a large group couldlikely clean the flesh straight off ya.

Here's one, biting away at a foot, spinning ina full circle to get as much of you as it can.

Theyre relatives of roly polies, whichactually evolved from ocean animals.

Excirolana chiltoni are found in shallowwaters on the coasts of places like Canada, the United States, Japan, Taiwan and Hong Kong.

But because theyre tiny, travel in smallgroups and have sand-colored camouflage, theyre pretty easy to miss.

Sand piranhas live in the swash zone, wheresaturated sand is washed over by waves.

Out of the whole wide beach, they stay in a band about the width of a car.

Once in a while they get stuck in a tidepool.

But mostly these crustaceans burrow in wet sand between waves taking cover from predators like these shorebirds.

The sand piranha digs in with some fearsome tools.

It holds steady with these hooks on its legs, then deploys this pair of mandibles.

They scrape away at their meal.

And these front legs, calledmaxillipeds, sweep food into its piehole.

And right now, you're on the menu.

It doesnt even try to ease your pain with anesthetic.

How rude!

And once it's down the hatch there'sno hiding what it had for lunch.

Dont worry!

Thats not human blood.

This sand piranha is chowingdown on something called a bloodworm ... named for its bright red worm blood.

Sand piranhas travel up and down the beach as the tides change.

Few creatures can survive therough-and-tumble life here in the swash zone.

So these crustaceans get priorityaccess to whatever washes up.

They help clean up all kinds ofwayward corpses, like this sea pickle ... ... keeping your favorite beach a little less stinky.

Now, you don't have to wait 'til one of thesetiny piranhas starts chomping onyour foot to know theyre around.

Watch out for these distinctivescribbles in the sand.

If you see them, keep moving yourfeet through that swash zone.

Or better yet dive in.