Dangerous Portuguese man o' war blow into Florida, South Carolina beaches along with spring breakers

Beachgoers beware: The Portuguese men o' war are ‘some of the most toxic animals in the world’ said biologist.

As spring break revelers flocked to beaches in South Florida and South Carolina recently, so did the dangerous Portuguese man o' war. Purple flags flew across Treasure Coast, South Florida and South Carolina beaches indicating dangerous marine life in the water. 

The Portuguese man o' war, related to a jellyfish, fires barbs loaded with toxin when something brushes against their tentacles. The cells still fire even if the animal is dead and washed-up on shore.

"These animals are some of the most toxic animals in the world," said Tony McEwan, Curator and Marine Biologist at the University of Hawaii's Waikiki Aquarium. "They're not very maneuverable animals, so their prey has to be immobilized very quickly."

Tentacles trail from a bubble/float with a sail. The animal was so named because it looked like an 18th-century Portuguese warship under sail. 

The float can be a gossamer blue, pink or violet up to 6 inches long and sits 6 inches above the waterline. They look pretty, but don’t touch.

"The Portuguese man o' war is not going to kill you but, it's going to be painful, and it's going to be uncomfortable and very itchy for a while," said McEwan then added the toxin could be fatal to someone with an allergy. "Then it slowly, slowly dissipates."

McEwan recommends staying out of the water if men o' war are present. Consider wearing shoes while beachcombing. The tentacles stretch well beyond the float, normally up to 3 feet but can grow to 100 feet long, according to NOAA. Keep them away from dogs’ curious noses and tongues too.


What to do if you get stung

"The consensus is that the best way to treat it is doing a couple of things," said Daniel Sasson, Research Scientist for the Marine Resources Research Institute in Charleston, South Carolina.

  • Spray or pour vinegar on the wound or where they stung you, which helps to deactivate the active firing cells.
  • Scrape the skin with a credit card. It removes stinging cells that haven't fired yet.
  • Soak affected skin in warm, almost hot water. The heat helps to destroy stinging cells that have not fired yet.
  • Try antihistamine for the itching.

How do they end up on the beach?

The species relies entirely on the wind and the currents, they can’t propel themselves. Strong onshore winds and storms like hurricanes blow the marine life onto the beach. The species are usually in groups, up to 1,000 or more, according to NOAA.


They prefer tropical and subtropical water but are found in nearly every ocean. 

One man o' war is actually a group of animals working together. Think of a colony of bees, each member has its own job. 

"They're really thousands of individual animals making up this one thing," explained Sasson. "You have some groups of those animals that are working together to make the float. Some of them are the defensive ones, the ones that actually have the stinging cells in them. Others are used for the digestion for the gut. And then you have some that are used for reproduction."

Just remember, these amazing creatures are better enjoyed from a distance.