Beachgoer Spots Shell Moving On Its Own — Then Realizes What’s Really Going On

“[T]hey are pretty rare to find … “Published on May 22, 2025 at PMThe other day, nature educator Brianna Varner was walking on the beach when she saw what appeared to be an empty shell scuttling around on its own.

Perplexed, she picked it up and turned it over — and saw the most adorable little face staring back at her.It turns out that the “empty shell” was actually occupied by a unique animal called a granulate shellback crab.

Similarly to hermit crabs, granulate shellbacks have soft exoskeletons and use shells other animals have left behind for protection.Because they blend in so well with other shells on the beach, most people have never seen one.“[G]ranulate shellback crabs aren’t new, but they are pretty rare to find,” Varner wrote on TikTok.Although a commenter on Varner’s video cleverly nicknamed granulate shellbacks “pancake cousins to hermit crabs,” the two species are actually pretty different.

Unlike their “pancake cousins,” granulate shellbacks use flat shells from bivalves, like clams or mussels.“These weirdos have extra legs on their back that help them grab onto bivalves,” Varner said in a TikTok.Granulate shellbacks then use suction to help their shell backpacks stay put.

They start practicing this technique from a young age — when they’re too small to use full shells, they use shell fragments.Granulate shellbacks periodically switch to larger shells as they grow.

When they’re caught in between homes, the crabs look a bit exposed, to say the least.But when they’re tucked into their shells, they’re surprisingly cute.“Their little claws have pink tips, which they often hold up to their face, making it look like they’re blushing,” Varner said.Native to shallow waters in the Western Atlantic, the crabs often get washed up on shore during storms.

So if you’re ever on the beach and notice a shell that looks like it’s moving on its own, try turning it over.

You might find a delightful surprise hiding underneath.