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07th Aug 2022

Tourists left ‘squealing’ as thousands of venomous crabs invade UK beach

Simon Bland


However the swarm isn’t what it seems…

A beach in the UK has been taken over by thousands of venomous crabs just as summer has arrived. The swarm has left tourists freaked out, with some “squealing” over the sight of so many crustaceans all in one place.

Images posted to social media appear to show a sea of giant spider crabs lurking just below the surface of the water on Porthgwidden Beach in St Ives, Cornwall. While the depths there are shallow, people hoping to go for a quick paddle have instead been met with countless hard-shelled companions while they wet their toes on the beach front.

Needless to say, many were left quite shocked at the sight of the creatures.


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A post shared by Kate Lowe (@cornish.coast)

Pictures of the crabs’ arrival were shared to the Instagram account of marine photographer Kate Lowe, who showcased the scale and scope of the spider crabs’ invasion.

However looks can be deceiving. According to experts, not all of the crabs pictured in these images are actual crabs. Turns out, these spider crabs shed their shells just before it’s time to move onto warmer waters and begin the mating process.

By carefully shimmying out of the back of their previous home, this type of crab – which has a venomous bite to ward off predators that’s harmless to humans – leave behind a fully intact exoskeleton. This, in turn, has made many tourists believe they’re coming face to face with huge numbers of live crabs when in reality, many are actually just empty shells.


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A post shared by Kate Lowe (@cornish.coast)

“I go snorkelling most of the time throughout the year, but I have never seen spider crabs in such numbers,” said Lowe, as per The Independent.

“When we turned up at the beach, it looked as though there were lots of dark rocks under the surface. But it turned out that there were thousands of crabs just two or three steps into the water.”

She continued: “It was just really incredible. They were only knee-deep. I was able to float on the water above them and tried not to step on them.

“A lot of the tourists were squealing at the sight of them.”

It is believed that these crabs have travelled to St Ives in search of warmer water temperatures, itself a possible result of climate change. Experts have said that seeing such an unusual sight on British coastlines could become more common in the future if the climate crisis continues and the weather continues to heat up.

Once they’ve shed their old shells, spider crabs must wait for their new shell to harden up before continuing to their breeding ground. While this species is typically brown in colour, spider crab shells have been known to turn bright red when they’re approaching the time to mate.

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