Bipalium kewense (Hammerhead Flatworm, featuring VIDEO), 14 March 2012

APRIL 2012 BONUS VIDEO: Video carnage has been added to this post:


This little bundle of nightmare is commonly known as the hammerhead flatworm, Bipalium kewense. Why do I say nightmare? These are predatory flatworms, people. They eat meat. They don’t have a respiratory system, but boy can they eat. They don’t have a circulatory system, but no worries: they can still eat, damn it. Hell, they don’t even has an anus… but that doesn’t stop these little monsters from eating. They eat and when they have excess discharge, they just vomit it out of their “mouth.”

But don’t worry. You can put your feet back down on the floor. They don’t eat people or any people parts (private or otherwise). Mainly, they prey on other invertebrates, particularly earthworms, snails and the like. If you’re an earthworm farmer, the hammerhead flatworm could be your economic undoing. And if you’re an earthworm? Forget about it. You’re doomed. Just kiss your little earthwormy ass goodbye. You’re toast. Game over, man.

Hammerhead flatworms are arbiters of destruction and mayhem in the world of invertebrates. They make contact with their prey, pin them down with their mucus, and inject their pharynx (located mid-body) into the victim’s tissue, breaking the fleshy goodness down for consumption.

This species is not native to North America, but instead hails originally from Indo-China (thank you, Indo-China!). It is now very much established in many areas of North America, particularly around greenhouses. Here in Valdosta, Georgia, we’ve got a good number of these flatworms patrolling the yard. I’ve seen several individuals (about 6-8 inches or so) slinking around the patio and hunting for prey during our warmer, more-humid nights.

You ask, So, Janson, why don’t you just cut them up when you see them? Death to the creepy flatworms! Flatworms be gone!

Well, cutting them up would be a icky-but-good plan if it weren’t for that pesky regeneration thing. That’s right, hammerhead flatworms can regenerate their body parts (including the “head” and pharynx). If and when they’re severed or cut into pieces, the flatworm’s pieces will regenerate the missing pieces. In other words: NIGHTMARE.

Do not cut into pieces.

Heh. Truth be told, I find these organisms to be fascinating and beautiful. A bit creepy, perhaps — but also very, very cool. Especially since I know they don’t want to eat my flesh. That’s okay by me. And earthworms? You’re on your own. Good luck!


TWO DAYS LATER… Two bonus photos from 16 March 2012:


~ janson

37 thoughts on “Bipalium kewense (Hammerhead Flatworm, featuring VIDEO), 14 March 2012”

  1. I don’t know why but for some reason this made me think of the monster in “Alien”!
    Very cool! Of course most of the earth worms we get around here are introduced species too.

    1. Leeches: one of the (very) few organisms that genuinely creep me out. I’ve had my share. Scorpions, too. God, I hated getting covered in scorpions back in Oklahoma. Pretty hard to avoid them when you’re pulling over logs in the Oklahoma forests… Heh. (Oh no, I just imagined scorpions regenerating… thank god *that* doesn’t happen…)

  2. Oh boy, life is rough if you’re a worm. Interesting how the hammerhead was still reaching out looking for more goodies to eat even when it was stuffed with the worm it was devouring.

  3. I just saw one of these hammer head worms in my back porch.It is about 7 inches long and I live in San Antonio Texas.What are these predators doing here in Texas ?

  4. Janson, I found your video and blog because these have been crawling over my (ground-level) porch near Stone Mountain GA (and I wondered what they were.)
    So, they are further north than Valdosta.
    Thanks for educating me – I had no idea what these critters were.

    1. Michael, thanks for the comment.

      Yeah, I keep seeing these hammerheads loitering about my back patio, especially in the morning hours, voraciously hunting the poor, feeble earthworms. They really are something. Makes me wonder how long they’ve been here — and how many there’ll be in ten years!!!

      ~ janson

    1. As a general, personal philosophy, I tend not to collect and ship the Platyhelminthes. Heh. But there’s a decent chance they’ll find their way to your neck of the woods. This is an incredibly adaptable species, it seems.

        1. I first observed “Plathelminthes, Bipalium kewense” (shovel or spade head flatworm) first ~8 months ago here near Slidell, LA. I’ve collected ~13 so far as I study them and shipped to researchers. -j

  5. Since the B-k flatworm is a predator of the earth worm, wouldn’t you want to eradicate them from your garden? How would you do it without making a bigger mess than what you have? Would pouring salt on them make them perish?

    1. Not being a gardener-type, I’m not sure, Karenf. I do know these hammerhead flatworms are remarkably resilient, though, and that –in Star Trek terms– resistance if futile. Heh. I did find this post from Money quote: “Unfortunately there isn’t any reliable solution for getting rid of these worms once they become established, since their requirements (moisture, darkness etc) are similar to those of the earthworms themselves. If you start seeing any of them, be sure to remove and kill them right away. It’s probably not a bad idea to move some of your worms to a more secure location (an indoor bin perhaps) so you at least have a partial insurance policy.” In other words, BRACE FOR IMPACT.

  6. There are actually two common species in Southern U.S. Bipalium kewense does feed on earthworms, but Bipalium vagum is actually beneficial; feeding only on snails and slugs. I raise dart frogs, which live in terrariums. I first found a vagum species 3 years ago and immediately destroyed it, only to learn later it was a possible savior for my terrarium plants from slug and snail damage.
    Finally found another today. I’m not quite ready to turn it loose in one of my vivariums, but I have already observed it eating a snail. I may try to culture more of these guys, while I test to ensure they will not create any harm.

    1. I haven’t seen any B. vagum yet, though I’m sure it’s only a matter of time. heh. We’re now in Ormond Beach, Florida, and I haven’t seen any Bipalium at all. Again, however, I’m sure it’s just a matter of time. These little’uns are impressive adept at doing what they do!!!

  7. Just saw one this morning at my parents house in Ormond Beach, Florida. I took a photo, because I really thought it was a tiny leech at first with a strange hammerhead. Plus when I picked it up with a long pin needle the thing wasn’t even concerned. I felt like it was smelling for me! Not kidding, not even the slightest bit worried about me.

  8. I just found one in Columbus, GA. 13MAR3016. I know that it preys on worms, and I want all the worms I can get in my gardens, but, I figure it’s like so many other things in nature….put there to help keep things in check. Population control. Much like the snake I found today as well…there to keep mice and what not in check. Found the snake while the neighbor’s cat appeared in sight with a chipmunk in its mouth. And the hammerhead flatworm….i found just feet below were a tree frog was perched. Checks and balances. This gardener is not worried about this fascinating yet disturbing creature!

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