Octopuses have been filmed taking night-time strolls out of the water and onto the shore on the coast of Ceredigion in Wales, UK.
More than 20 of the brainy cephalopods were spotted crawling out of the water after 10pm on Friday, when a local tour company manager and a group returned from a sunset trip.
“They were coming out of the water and crawling up the beach. We don’t quite know what’s causing it,” Brett Jones, owner of dolphin tour company SeaMôr Dolphin Watching Boat Trips, told Wales Online.
“Perhaps it’s because the sea has been quite rough recently, but I’ve never seen anything like it before. They were walking on the tips of their legs.”
He said a friend told him they’d been doing it on Thursday night, too.
It’s not the first time octopuses have been seen perambulating out of the water. In 2011, an octopus was filmed crawling over dry land at the Fitzgerald Marine Reserve in San Mateo County, California.
And last year, Inky the octopus made international headlines when he escaped his tank in the National Aquarium of New Zealand, crawled across the room, disappeared down a drainpipe and fled out to sea.
The behaviour isn’t uncommon for octopuses that live near the shoreline, according to marine invertebrate expert Julian Finn of Museums Victoria in Australia. It’s just that most octopuses are nocturnal, so reasonably unlikely to be seen by humans when they go for a wander.
As for why they do it, well, it’s probably because of food. When the evening tide goes out, “many octopus species emerge to hunt in the pools of water left behind by the receding tide,” Finn told Scientific American in 2010.
Octopuses have gills, and need to be in the water to breathe, but they can survive for a short period of time if their skin stays moist, Finn said. This is because they can absorb some oxygen through their skin from the water.
Whatever the Ceredigion octopuses are up to, the gamble unfortunately didn’t pay off for a few of them. Jones reported on Facebook that he’d found a few dead ones on the beach at Clare Oxenham the following morning.
He also helped a few back into the sea.
“We collected the ones that were totally out of the water, and plopped them back in at the end of the pier, hopefully saving them from getting stranded,” he wrote.