Warning to dog owners as mysterious jellyfish-like creatures spotted on Cornish beaches

By-the-wind sailors are hydrozoans – a colony of tiny individual animals called hydroids. Credit: Cornwall Wildlife Trust

Cornwall Wildlife Trust is warning people to look out for tiny jellyfish-like creatures washing up on beaches this weekend.

By-the-wind sailors look like jellyfish, but are in fact hydrozoans – a colony of tiny individual animals called hydroids.

Like the Portuguese man o' war, their sail allows them to catch the wind and travel on ocean currents. However, they cannot sting human beings.

Cornwall Wildlife Trust said in a Facebook post: "These mysterious and beautiful creatures have recently been spotted on our Cornish shores again!

"You might have seen these if you’ve been taking a stroll along the beaches recently."

By-the-wind sailors are often blown up by strong winds. Credit: Tracey Williams

The trust advised dog owners to keep an eye on their pets when walking along beaches this weekend.

Matt Slater, Marine Conservation Officer at Cornwall Wildlife Trust, said: “Fortunately, the stings are not powerful enough to harm humans or dogs, although it is not advisable to touch them and then touch your face and eyes, as they may cause skin irritation.

"Dogs love eating them – they have a strong smell of the ocean – but I don’t think they are good for them."

By-the-wind sailors were seen across Cornwall last May, including on Newquay’s Fistral beach, Lansallos beach, Harlyn Bay, Port Gaverne, Port Quin, Mawgan Porth, Porthtowan, Perranporth, Polly Joke, Trevellas Cove, Gwithian, Portreath, Praa Sands, and Crantock.

Some of the creatures were no bigger than a 50p coin, while others were more substantial, up to 10cm long.