Toxic sea creatures 'joined in a line' on Aussie beach spark urgent warning

The strange-looking animal is best left alone.

Aussies are being warned to keep a watchful eye over their children and pets when at the beach, after a "toxic" sea creature was spotted in the water.

"So many sea hares just in one spot," a woman posted online, along with a photo and video of the shoreline where a hairy-looking animal could be seen. "Apparently when all joined in a line it's them mating," she explained, before adding that the animals "may be neurotoxic to dogs" and advised people to keep their pets away.

Hairy sea hares in shallows at beach
Sea hares can squirt out a purple dye which creates a smokescreen for potential predators at the beach. Source: Facebook

She was right to warn dog owners about hairy sea hares, also known as bursatella hirsuta, according to Dr Daryl McPhee, Associate Professor of Environmental Science at Bond University. "Sea hares are basically a sea slug and have an internal shell and they graze algae," he told Yahoo News Australia.

It's their diet that makes them dangerous. "They can squirt out a purple dye which creates a smokescreen for potential predators," McPhee said. "Their level of toxicity can be highly variable between individuals because they get their toxins from the algae that they graze."

Keep an eye on your dog

The woman made the discovery at Tallebudgera Creek on the Gold Coast, but pet owners around the country are being advised to watch out, as they're found around most of the Australian coast. "You shouldn't let your dogs lick them," McPhee said. "And children shouldn't play with them either. It would just be discomfort if they touch them and then rub their eyes in particular."

He urged anyone whose dog may have come into contact with a sea hare to keep a close eye on them. "Just monitor them for symptoms," he explained. "There might be nausea and spasms for the dog. And if a dog does get mysteriously sick after a walk at the beach and licking something that looks like a sponge, take them to the vet."

Aerial shot of Tallebudgera Creek on the Gold Coast, Queensland
The creature was spotted at Tallebudgera Creek on the Gold Coast. Source: Google Maps

Dog's death likely caused by sea hare

In 2018, a four-month-old Labrador named Ned died after a trip to the beach in Western Australia's southwest. Ned's owner Max Beckerling told Yahoo News Australia at the time Ned appeared fine until around 45 minutes after they'd left the beach, when he saw the pup lying lifeless on the floor. "I thought he was sleeping. But he was dead," Max recalled. He believes it was a sea hare that caused Ned's death, which prompted authorities to issue a warning to dog owners to keep their pets away from the creatures.

The secret sex life of sea hares

As for what the sea hare — or rather, sea hares — were doing on this occasion, McPhee gave a bit of an explanation on the mating habits of the species. "They're what's called simultaneous hermaphrodites," he revealed. "So they're both male and female at the same time. They line up like that because the male parts of one fertilise the female parts of another whilst another male fertilises the female parts of the one that's fertilising the male." He added there were likely five sea hares joined together in the images.

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