Ghost shrimp chimneys, clam “keyholes,” crab burrows—what those tiny holes tell you about the beach

Most holes you see on Gulf beaches are made by living neighbors—clams, crabs, worms, and ghost shrimp. Their patterns help you read the shoreline, find shell lines, and time a better shark-tooth hunt.

Quick ID guide

• Clam “keyholes” (coquina/Donax): Dime-sized ovals that appear and vanish with each wave in the swash zone. Step nearby and you’ll see tiny jets of water as clams dig down.
• Ghost shrimp chimneys: Short, crumbly mounds with a hole on top, usually lower on the beach at low tide. Telltale pellets around the rim = a busy engineer below.
• Fiddler/ghost crab burrows: Round openings up to quarter-size, often higher on the beach near the wrack line. Look for tracks and little sand fans outside the door.
• Worm casts: Small spaghetti-like coils of sand with a pinhole nearby—deposit-feeding worms leaving neat “sand noodles.”
• Mole crabs (sand fleas): V-shaped dimples that reappear wave after wave along the breaker edge; great bait, better indicators of active food lines.
• Stingray feeding pits: Shallow dish-shaped scoops on sand bars or in very shallow water; often in clusters. Do the stingray shuffle—slide feet so a ray can scoot away.

Why this matters

• Life = structure. Where critters churn the sand (bioturbation), tiny shells and micro-teeth concentrate. Work the micro-hash around those zones.
• Patterns predict finds. Clam keyholes lining up with a fresh shell line = your cue to slow down and scan.
• Timing tip. After a breezy onshore day or an overnight tide swing, new holes and new shell lines usually appear together.

Arthur’s note: “When the sand breathes, treasures rise—follow the little doorways and you’ll find the pantry.”

Ghost crabs

The holes that ghost crabs create range from a few inches to about half an inch in diameter and serve as protective tunnels. Ghost crabs spend most days in their burrows and come out at night to scavenge. They wet their gills by taking water from moist sand or running to the shoreline for a quick splash—stay too long and they can drown. With strong claws, speedy legs, and coloring that matches dry sand, they can look like tiny ghosts darting along the beach.

Ghost shrimp

Ghost shrimp holes are often ringed by small pellets that resemble sprinkles. These nearly translucent engineers have legs and claws up front but soft, vulnerable backs, so they burrow deep—sometimes several feet—to stay safe and moist. They pull in seawater to feed on plankton, then push that water back out, keeping the burrow clean and building those “sprinkle” rings at the surface.

Sandworms / lugworms

Sandworms build U-shaped homes with two openings. One serves as the feeding “pit” where they ingest organic particles along with sand; the other is for ejecting waste. Look for a pinhole paired with a coiled sand cast—that’s your giveaway.

Sand dollars

If you notice two or more small holes very close together, be gentle—sand dollars often bury just beneath the wet sand. Using tiny spines, they move water and sand to plunge below; the “keyhole” shapes are what we see from above. Sand dollars need water to survive, so please don’t remove live ones.

There’s still plenty of life we haven’t met beneath our feet. The more we watch and learn, the better we care for the beaches that care for us.