A man-of-war is a colony of hydroids, tiny animals which “work together to form a total package,” says George Burgess of the Florida Museum of Natural History.
Therefore, they are not jellyfish, though they strongly resemble their cousins of the sea.
They have no propulsion system and depend on currents and wind for mobility in warm tropical and subtropical waters worldwide.
Man-of-wars have biological structures called polyps that serve various functions such as feeding, defense, and reproduction.
Man-o-war tentacles can reach 165 feet (50 meters) long and are covered with nematocysts—“coiled, barbed bodies” that look like a squished Slinky, Burgess says.
For us humans, though, a man-of-war sting can cause welts and severe pain—and allergic reaction can affect a person’s breathing, White says. “Drowning is a concern.”
Burgess, an asthmatic, needed hospital treatment after a sting and advises simple caution in the ocean.
“Live your life,” he says, but “remember when you enter the sea that it’s a wilderness experience.”
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