Thousands of 'penis fish' litter California beach

Urechis unicinctus, known as penis fish, innkeeper worm or spoon worm, is shown in this file photo at a market in South Korea (Photo: iStock / Arrlxx)

TORONTO — Before you avert your eyes, they’re not what you might think they are.

The thousands of pink, pulsating phallic creatures that were discovered on a northern California beach after a recent storm are actually marine worms.

The 25-centimetre-long worms are officially named Urechis caupo, but they’re also known as “fat innkeeper worms” or “penis fish.”

According to the magazine Bay Nature, the non-segmented marine worms were uprooted from their deep burrows in the sand on Drakes Beach, located approximately 100 kilometres northwest of San Francisco, during a storm earlier this month.

Biologist Ivan Parr, who writes for the magazine, said this particular species is only found between southern Oregon and Baja, Calif. with most of the sightings between Bodega Bay and Monterey.

“Whether or not you feel privileged by its presence, U. caupo is an almost uniquely California experience, perhaps having the best claim for State Worm,” he wrote on Tuesday.

While Urechis caupo is only found in North America, another species in its family called Urechis unicinctus is actually a well-known delicacy for people in East Asia.

Despite their awkward shape, Parr explained that the organisms are actually perfectly designed for a life spent underground.

“Within a beach or mudflat, it digs a U-shaped burrow extending a few feet in length but no wider than the worm itself,” he said. “The burrow’s front entrance pokes up like a little sand chimney.”

The biologist said the worm is able to slide up and down the chimney of its burrow in order to suck up plankton, bacteria, and other fare.

While they may seem rare, Parr said the worms are actually quite common and there is evidence they have existed for hundreds of millions of years.

“The innkeeper is a survivor with fossil evidence of U-shaped burrows dating back 300 million years,” Parr said.

As for the creatures’ recent displacement on Drakes Beach, the nature magazine said strong storms, especially in El Nino years, are capable of upending the worms’ burrows and leaving them exposed on shore.

It’s still unclear, however, if these powerful storms will have long-term consequences for the species, Parr said.