Is that a snake? Nope, it’s a foot-long invasive flatworm (and you might want to kill it)

You probably already know that North Carolina has lots of snakes .

So you might not give a long, skinny thing slithering along the ground a second thought. “Yep,” you’d say to yourself, “just another snake.”

But alas, it might not be. North Carolina has some flatworms that can be up to a foot long and as skinny as a worm snake …. Except this one is actually a worm.

A Triangle resident posted a photo of one of these foot-long flatworms to a Hillsborough Facebook group, saying she’d seen them two times within a few months. (The News & Observer was not able to get in touch for more information.)

The NC State Extension Office has lots of information about these worms — which can be called Terrestrial Flatworms, Land Planarians and Hammerhead Worms — on their website .

“Although alien-looking and often off-putting, these worms are a natural part of many ecosystems. While some species are native to North Carolina, others are foreign in origin, having been transported here through human endeavors over the years,” the Extension office wrote.

What to know about North Carolina’s invasive flatworms

These flatworms are known to kill other native worms, snails and slugs, making them a damaging predator in our region. They also produce a protective toxin (more below) and can carry a harmful parasite.

• There are five species in North Carolina . Many have been here for years, even decades.

Here’s how NCSU describes them:

1. Bipalium kewense is typically a darker brown color with five lines along the length of the body (the central and side lines thinner than the others) and a dark, broken collar around the neck.

2. The mollusc-eating hammerhead worm ( Bipalium vagum ), has a short body and wide head with a single dark stripe down the back and a distinct collar around the neck.

3. Diversibipalium multilineatum is pale or straw yellow colored and has five thin stripes down the length of the body with the central one continuing onto the head. It also lacks a collar around the neck region.

4. The wandering broadhead planarian ( Bipalium adventitum ) is light colored as well, but has a single thin stripe along the back, no collar around the neck and may have a more rounded head.

5. The three-lined land planarian ( Bipalium pennsylvanicum ) has three dorsal lines, the middle line extending onto the head and lacking a collar around the neck.

Visit content.ces.ncsu.edu/terrestrial-flatwormshammerhead-worms for photos of each worm.

The worm posted to the Hillsborough Facebook group is likely Diversibipalium multilineatum , said Matt Bertone , director of the NC State Plant Disease and Insect Clinic . These have five thin stripes down its body and can get extra long.

Other things to k now about these invasive worms:

• They’re many colors , which can help identify the correct species. Many are striped and brown, but others can be black, gray or even blue.

• They’re only found in wet environments , since they require moisture to survive. You can find them under rocks, in leaf litter or under other debris that covers the ground to keep it moist.

• They can reproduce in a few ways . Flatworms can reproduce sexually, when the worms mate and lay cocoons. But they usually reproduce asexually — the body breaks, and each segment becomes a new worm .

This means you shouldn’t slice them up to kill them , since you might just double their population. (More below on how to properly kill them.)

Are NC flatworms toxic to humans?

Not unless you’re eating them, Bertone said.

“These worms are not toxic to the touch , and several would have to be consumed to harm a person,” he said.

But at least two members of the hammerhead genus Bipalium are the first land invertebrates known to produce tetrodotoxin , which is the same potent toxin that pufferfish produce , NCSU says. It’s thought to help them defend themselves and overcome predators.

Its impact to humans is likely minimal unless the worms are ingested, NCSU says. Still, after handling the worms, you should thoroughly wash your hands to be extra safe.

Should you kill NC flatworms?

You can , but you don’t have to. They’re well-established in parts of North Carolina, making it “an uphill battle and likely not worth the energy,” Bertone said.

Here’s how NCSU recommends killing them:

• First and foremost you should not cut up the worms to destroy them , as cut fragments can become new worms.

• If you can pick them up with tweezers or gloved hands, you can kill them in rubbing alcohol or put them in a bag and freeze them .

• To avoid direct contact, you can also use salt to effectively eliminate individual flatworms. (Limit the applied amount if near plants, as it can harm vegetation.)

Note: These management strategies will also kill earthworms , which are important players in soil health. So earthworms should be removed during flatworm treatment to protect them.

What is an invasive species?

“By definition, an invasive species is one that causes harm, which can come in many forms,” said Kelly Oten , an NCSU Extension specialist in forestry and environmental resources.

Invasive species can:

• Displace native species (like the invasive plant kudzu, which blanket and choke out areas of forests)

• Impact our crop production (such as kudzu bugs, which can devastate soybean crops)

• Kill our native plants (like the emerald ash borer, which is killing our ash trees)

• Cause animal or human health issues (such as fire ants or the Asian tiger mosquito)

“If we’re talking about an invasive species, that implies some harm is being caused. It can be environmental, economical or a health concern,” Oten said.

“Of course, each case is different, so the ‘kill them all’ mentality might be overkill for some.”

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