The Invasive Species Making Mississippians Nervous

Quick Take

• Your first instinct for killing this worm could make your problem exponentially worse. See safe disposal methods →
• This creature hunts prey far larger than itself using a method that sounds more like a horror film than biology. Discover its hunting behavior →
• Touching one bare-handed isn't just unpleasant. Experts say there's a specific medical reason to keep your distance. Read the health warning →
• A worm that has been quietly living in the US since the 1800s is suddenly making headlines, and the reason it matters now is tied directly to your backyard. See why it matters now →

Behind this slightly scary Instagram post is a serious message about an invasive species. The post features a close-up shot of a hammerhead worm, a bizarre-looking creature that should not be in Mississippi! Read on to find out more.

What Is the Invasive Hammerhead Worm?

Hammerhead worms are members of the subfamily Bipaliinae. They are tropical and semi-tropical land worms originating in Asia and Madagascar. These worms are easily recognized by the distinct crescent- or fan-shaped structure at one end of their body – the ‘hammerhead’. Some only reach a few inches in length, but others can grow to several feet.

Hammerhead worms are carnivorous, generalist predators. They locate potential prey using chemoreceptors along their heads. This is how they hunt the humble earthworm! They can follow earthworm mucus and body secretion trails on or just below the soil surface. Once they have found a victim, they wrap around it and ‘cap’ the earthworm so it can’t escape. They then use their digestive organ, called an everted pharynx, to break down the earthworm’s body. Using this efficient hunting method, they can attack earthworms much bigger than they are.

Mississippi Warning About Hammerhead Worms

The species introduced to the US is Bipalium kewense and has been in the US since 1891. They were probably imported with plants and soil. The Mississippi State University Extension Service has recently issued a warning to the public that they should be on the lookout for them. This species can grow up to a foot long and has a distinctive hammer-shaped head. Earthworms are critical for the maintenance of healthy soil that gardens and farms rely on.

If you spot one, however, you should not touch it. In a press release, Dr. Jermaine Perier, an MSU Extension entomologist specializing in vegetables, fruits, and nuts, said, “Their mucus can be an irritant, and some species produce neurotoxins.” Pets can get sick if they eat them.

You should only pick them up using gloves. Just as importantly, you should not try to cut them in half with a spade. These worms can generate another body from fragments of body parts. If you try to cut them in half, each piece can regenerate into a new worm, resulting in even more worms.

Instead, place it in an airtight container and dispose of it by adding salt or soapy water and leaving it in direct sunlight. Alternatively, soak it in ethanol, alcohol, or hand sanitizer.