Blue crabs live their entire lives in the water. That’s where they eat, breed, and even breathe. So, some marine scientists were a bit astonished when they saw blue crabs popping out of muddy pits on shore to grab fiddler crabs.

Blue crabs are found all along the East Coast and the Gulf of Mexico, on the bottoms of shallow bays and estuaries. They have been seen to dart out of the water to grab prey, but only by a few feet.

But in September of 2021, researchers in Virginia saw them emerging from small pits in the sand. It was low tide, so some of the pits were up to a couple of hundred feet from the water.

In some cases, the crabs “exploded” from the pits to snatch fiddler crabs that were close by. In other cases, they crept out of the pits and snuck up on their prey. They then dragged the fiddler crabs back to the pits for a leisurely meal.

And it was clear the blue crabs had been hanging out for a while. The scientists said some of the pits were littered with fiddler crab claws “like the discarded bones of villagers outside a dragon’s lair.”

The researchers returned a couple of weeks later with cameras to confirm the goings-on. They recorded the crabs digging their pits, switching to new ones, and even kicking other crabs out of their pits.

The scientists found one other report of such behavior, but nothing had been formally recorded. So, this is the first confirmed instance of blue crabs living—and attacking—from outside their usual watery environment.