When a strange-looking "tentacled creature" washed ashore in Devon, England this week, local residents quickly got busy with some guesswork. The mass of fleshy tubes might look peculiar, but it's actually nothing more than a bundle of barnacles.  

The list of IDs proposed online featured some decent guesses: everything from bull kelp to a colony of mussels. What you're looking at, however, is a group of goose barnacles, likely Lepas anatifera.

These offshore invertebrates tend to inhabit tropical and subtropical waters (which explains why Devon's beachgoers were surprised by the sight of them), but because they often settle on drifting objects, they can also be swept into colder climes. In fact, goose barnacles turn up in these parts nearly every year.  

A similarly "dreadlocked" log puzzled locals when it washed ashore on New Zealand's Muriwai Beach last year.

Goose barnacles photographed on Muriwai Beach, New Zealand last year. Image © Melissa Doubleday/Facebook

But why the "goose" in goose barnacles? It comes down to a strange bit of avian lore involving a black-and-white bird tellingly known as the barnacle goose (Branta leucopsis).

The barnacles' chalk-white shells and rubbery stalks evoke the shape of a long-necked bird, and that resemblance gave rise to a medieval myth: people once thought barnacle geese did not hatch from eggs but instead developed out at sea, inside the goose barnacles. 

"[The barnacle goose] overwintered in Ireland and Scotland, but few saw where it nested. When locals found the black-and-white barnacles floating to shore on pieces of driftwood, the answer seemed obvious," writes Kristen Minogue over at the Smithsonian Environmental Research Center. "They concluded that the geese did not have nests at all. Instead, these barnacles must be fruit that, when ripe, gave birth to the geese."

Of course, we now know that, like their avian counterparts, these filter-feeders don't begin life attached to floating objects. In the larval state, goose barnacles float through the water column as tiny plankton. As they mature, a muscular foot (or "peduncle"), paired with a biochemical adhesive that rivals dental cement in strength, allows the barnacles to stake their claim on objects. Buoys, bottles and sea turtles (in one case, even the remains of a rocket!) have turned up covered with barnacle fixtures. 

Barnacles sieve prey from the water using feathery appendages called cirri, and because some of the onboard barnacles in the Devon sighting were still displaying this behaviour, we'd wager that Clarke-Wardle's find hadn't been ashore too long. (These animals must eventually close up shop when exposed to prevent desiccation.)

In 2014 goose barnacles made the news when footage emerged from Ocean Shores, Washington of a beached boat covered with worm-like attachments.

It's also possible, however, that Clarke-Wardle incidentally prompted some of the individual barnacles to open when she poured water over the log to keep it from drying out – though that seems less likely. 

Clarke-Wardle notes that the tide had gone out quite far by the time she happened upon the scene. "I just hope it got washed back to sea," she says.


Top header image: Steve Rawley/Flickr