David Ford likes to walk Drakes Beach whenever he can. On December 6, after a storm, he walked along the Bay Area beach and noticed hundreds of seagulls feasting on something in the sand. The sight of what they were eating shocked him.
The creatures were pink and roughly six inches long with a little nipple-like protrusion at the tip. Frankly, It looked as if hundreds of thousands of dicks had washed ashore. “I didn’t expect to see such bizarre creatures on the ground,” Ford told Motherboard over the phone.
“I had no idea what they might be…it went on for two miles,” Ford said. “I walked for another half hour and they were scattered everywhere. There were seagulls lined up the beach the whole way having eaten so much they could barely stand. A quarter of them looked like they were still alive. The rest were dead, they had a dead sea-creature smell.”
Ford took pictures of the creatures and searched the internet to solve the mystery of the beached cock swarm. He discovered they were a species of worm called fat innkeeper worms, or "penis fish." Ford reached out to Bay Nature, which runs a column called “Ask a Naturalist” that explained the worms' strange shape and guessed at why they may have have washed up on the beach en masse. According to biologist Ivan Parr, writing for Bay Nature:
“Yes, the physical design of the fat innkeeper worm has some explaining to do. But the fat innkeeper is perfectly shaped 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. The burrow’s front entrance pokes up like a little sand chimney. These can be seen clustered around the low tide line of a mudflat or sandy beach. The backdoor is marked by a pile of worm castings, which get projected out the end of the tunnel with a blast of water from the worm’s hindquarters.”
Par wrote that he didn’t know why the penis fish ended up on Drakes Beach, but guessed that it had something to do with the recent storm and the fish’s penchant for sandy habitats. This isn’t the first time this has happened, either.
“We’re seeing the risk of building your home out of sand,” Parr wrote. “Strong storms—especially during El Niño years—are perfectly capable of laying siege to the intertidal zone, breaking apart the sediments, and leaving their contents stranded on shore.”
“When the tide is in, the worm slides up to the chimney of its burrow and exudes a sticky mucous net from a ring of glands,” Parr wrote. “Sometimes you can see these mucous nets, looking like decaying jellyfish, draped around the burrow entrance. The worm continues to secrete as it slips lower into the burrow, generating a slime-net that stretches from the chimney to the worm’s mouth.”
Seeing such strange sights is one of the reasons Ford loves to walk the beach. “Those creatures are in a phylum all by themselves with three other things and have been on their own path of evolution for 400 or 500 million years,” he said. “It’s a wonder of their fertility. There must have been hundreds of thousands of them.”
The innkeeper worms weren’t the only odd site on the beach that day. “There were a couple of elephant seals, which are rather phallic themselves,” he said. “There was a carcass of a sea turtle, which don’t live around here, and the carcass of an angel shark. The ocean is full of mysteries.”