Jellyfish Gone Wild — Text-only | Flash Special Report
Most species of jellyfish and jellyfish-like animals are not harmful to people. But all true jellyfish and some species of jellyfish-like creatures sting; a single stinging tentacle may be studded with thousands of stingers. Stinging gelatinous creatures cause various reactions in people, ranging from no noticeable sensation to rashes, and in relatively rare cases, death.
Beware: Gelatinous creatures that are harmful to people live in every ocean. Common harmful species include:
· THE PORTUGUESE MAN-OF-WAR: The pain of this creature’s sting has been compared to that caused by being struck by lightning.
· THE LION’S MANE: Clumping into giant formations resembling horrifying hairballs, the tentacles of the Lion’s Mane jellyfish--which may each reach 100 feet in length--are lined with toxic stingers.
· PELAGIA NOCTILUCA OR THE MAUVE STINGER: After being stung by Pelagia in the Mediterranean, one swimmer described the experience as “feeling like 1,000 needles were simultaneously sunk into my skin.”
HOW THE STINGER WORKS
Most species of jellyfish cannot target or stalk prey. Instead, these brainless, spineless creatures--lacking malice--passively wait for prey to brush against their stingers, which automatically fire when touched. Even dead jellyfish, beached jellyfish and detached tentacles can keep stinging.
Wound like a tightly coiled harpoon, the jellyfish’s stinger sinks poison into prey with about as much pressure as a gun fires a bullet. The discharge of the jellyfish’s stinger is one of the quickest movements in nature.
Box jellyfish--named for their squarish bells--are among the most feared types of jellyfish. Thus far, about 30 species of box jellyfish have been identified; some are more deadly and painful than others.
The Medical Journal of Australia reports that lethal or potentially lethal box jellyfish “occur worldwide, around every major land mass in the tropical and some subtropical oceans,” and that deaths and serious injuries from them “are more common than previously believed.”
Twenty to 40 people die from stings from box jellyfish annually in the Philippines alone. But because death certificates are not required in many countries within the range of box jellyfish, worldwide fatalities from box jellyfish may be seriously underestimated.
The box jellyfish known as Chironex fleckeri is the world’s most venomous animal. A Chironex fleckeri can kill a person in under three minutes--a world’s record. On average, this animal kills one person per year in Australia.
Other species of box jellyfish cause Irukandji syndrome: a suite of agonizing symptoms that may include heart failure. There are two confirmed deaths from Irukandji syndrome on record--both occurred in Australia. But scientists suspect that additional deaths from this hard-to-diagnose syndrome, which may be caused by as many as 10 jellyfish species, have been wrongly attributed to heart attacks and other causes.
Irukandji syndrome is most common in Australia. But Irukandji syndrome, or an Irukandji-like syndrome, has been reported in tropical waters around the world, including Hawaii, Florida and other U.S. locations.
A HUMDINGER OF A STINGER
In Australia, about 10,000 people are stung annually by the Portuguese man-of-war. This animal’s sting is famous for its excruciating pain. Credit: Laurence Madin, Woods Hole Oceanographic Institution
GIANT, STINGING TENTACLES
The tentacles of the lion’s mane jellyfish can grow longer than a 100-foot blue whale, the largest animal on Earth. The largest lion's manes live in Arctic waters. Credit: Kip Evans, NOAA