If you frequently walk the beaches of Sanibel, you’ve most likely experienced an invasion of white, paper-like, tubes scattered all over the beach. The identification of this object has stumped even the most experienced beachcombers. These tubes are the self-created homes of a parchment worm (Chaetopterus).

Parchment worms tunnel into the sand using spines along their body and encase themselves in sediment, building a u-shaped tube, to live inside. The worm itself looks like something straight out of a sci-fi thriller but they’re harmless creatures. They belong to an extensive family of bristle worms (polychaetes – poly=many; chaetos=fine hair). Their bodies can be separated into three sections: a shovel-like mouth with whiskery appendages at one end, wing-like structures in the middle to form food bags, and paddle-shaped segments used to pump water through the tube at the other end.

As water passes through the tube, plankton and detritus are caught in their mucous-y web and collected in food bags. The bags are then passed back to the mouth where they’re swallowed whole. The adult worm spends its entire life in the tube, so typically when they wash ashore, the worm has died and the tube is lifted out of the sediment by wave action.

Parchment tube worms are bioluminescent too! They can emit blue light if threatened. When they sense a predator, they’ll move to the opposite end of their tube and send out bright blue flashes. The worm hopes to catch the attention of an even larger predator to save them from their current attacker.