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Hammerhead Flatworms Are Creepy and Spreading Up the East Coast

Hammerhead worm Credit: Wikimedia Commons

Another creepy creature is making its way up the eastern seaboard. Invasive hammerhead worms that are about 22 inches long and contain a neurotoxin (poison) are spreading up the southeastern coast (e.g., Florida, Georgia) north to Washington DC, Virginia, Maryland, Pennsylvania, NJ and elsewhere. Yikes!

The flatworms (Bipalium) originally came from Asia. They contain tetrodoxin (TTX), which causes paralysis of the muscle tissue. It's the same toxin found in puffer fish! But what makes the worms ultra-creepy is that if one gets broken up into mutiple pieces, each piece can regenerate to become a fully functioning worm!

Biologists say they are not a danger to humans unless handled (can cause skin irritation) or eaten (many of them). They can be killed by pouring some salt on them, and then dispose by placing into a plastic bag. Don't handle with bare hands - use a stick or wear gloves.

Excerpts from Washington Post: Toxin-secreting hammerhead worms are invading the D.C. area. How to stop them.

The hammerhead worm immediately stops you in your tracks. The striped flatworm slithers like a snake and resembles a piece of whole-wheat spaghetti, led by its mushroom-shaped head. And it also secretes tetrodotoxin, the same debilitating neurotoxin found in puffer fish.

...Then, it broke into multiple pieces. Each piece can function as an independent worm, squirm away and regenerate into more slithering, sticky worms.

“These worms are one of the craziest creatures I have ever seen and are pretty darned creepy,” said entomologist Michael Raupp, who drove to Peanut’s house and collected a sample of the worms. Raupp, a professor emeritus at the University of Maryland, theorized the worms may have been introduced into Peanut’s yard with an application of mulch or with strips of sod that were placed near the driveway.

The hammerhead worm (Bipalium) is an invasive flatworm from Asia, probably spreading to many new locations through the exportation of exotic plants. 

Research shows the genus has spread across the world, especially along the East Coast of the United States. Computer models show the Eastern United States will continue to be a suitable environment for the worms, as the climate warms.

The good news is that the worm isn’t a threat to humans unless ingested or handled, biologist Amber Stokes said. “Yes, they are poisonous, but they are so small that you would have to actually eat many of them to have any ill effects. I feel pretty doubtful that most people are interested in eating them,” Stokes, a professor at California State University at Bakersfield, said in an email.

Additionally, like many flatworms, they can carry parasitic nematodes. They can also be dangerous to pets if ingested. But the worms are sensitive to light and don’t usually appear when the sun is out, leaving most of the day worm-free for people and many pets.

Other creatures, though, suffer a deadlier fate. With no natural predators in the Washington region, hammerhead worms are voracious hunters of other invertebrates that are often much larger than they are, including earthworms, snails, and slugs.

 ...They have been observed crawling on an earthworm and rubbing their head over the earthworm, at which stage scientists think the hammerheads are using their toxin. Shortly after, the earthworm becomes less mobile. The hammerhead then secretes digestive enzymes and sucks the liquefied tissue into its gut. When digestion is complete, the worm’s mouth also serves as its anus.

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