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Hammerhead Flatworm

Terrestrial Planarian


13" worm. Tan in color, with a lighter tan strip that ran the length of its body with another dark super think strip inside the tan strip. It had a dark brown ring near the base of the head. Smooth, shiny texture. and a hammer shaped head. Body was flat, like a tapeworm... Ick!


this thing crossed my path yesterday. it is gross. What I do find interesting is the shape of its head. When it moved it seemed like its head was what sensed the obstacles and helped guide the direction of its movement. It would touch the object with this odd shaped appendage and then move around or over it. I do not think it has eyes either. And it moved pretty fast relatively speaking. It would be kind of interesting to see what its role is in life.

1 species ID suggestions

KarenL 5 years ago
Hammerhead flatworm
Platyhelminthes sp. All About » The Hammerhead Flatworm


Moved to the Other category

SamanthaCraven 4 years ago

Please consider adding this spotting to the new flatworms mission!

Ivan Rodriguez
Ivan Rodriguez 4 years ago

What happened to your comment Jungle Mamasita? It had great points, and I completely agree that something even like this hammerhead worm must serve some important role in nature.

Ashish Nimkar
Ashish Nimkar 4 years ago

Hahaha... No one harmful than Human.....!!

ScottRasmussen 5 years ago

What fascinated me is that some of the species mimic coral snake coloration. I've certainly seem mimicry across families, but never across entire phyla.

KarenL 5 years ago


Ivan Rodriguez
Ivan Rodriguez 5 years ago

I just might never go outside again.

JungleLoveMamasita 5 years ago

yeah, AshishNimakar, some with vibrant colors too, which was surprising.

I also checked out the link that KarenL gave learned even more.

Here are my clippings from this site:

The hammerhead flatworm does not help to control other pest populations as most worms do. They actually kill and eat earthworms, exclusively. The hammerhead flatworm is considered a parasite and it devours its only prey by pushing its throat outside if its mouth and snapping up any part of the earthworms body. It melts the earthworms body with an enzyme and slowly eats it until the earthworm is completely consumed.

For the most part, hammerhead flatworms can survive just about anywhere, so no one region is 100% safe. While this unique worm can survive in scorching hot to freezing climates, they may suffer somewhat in drier regions.

So if you have a garden, these guys will kill the earthworms that are there protecting your garden.

And it says that if you try chopping it up all the pieces will turn into more hammerhead worms. the only way to kill it is to 'completely' dissolve it by pouring vinegar, salt or citrus oil directly on it.

Okay, now can I hear a loud, Ewwwwwww.

Ashish Nimkar
Ashish Nimkar 5 years ago

Thanks Scott for Visualised link... They are really surprising creatures...

JungleLoveMamasita 5 years ago

Ewwww. that is what i think. Thanks Scott, I checked out your link and about the 5th or 6th picture down there is one that looks like the pic I took. And the guy is holding it!!! I am coming to grips that even slimy creatures like this one has a place in the symbiotic circle of life, but be patient with me.

Ivan Rodriguez
Ivan Rodriguez 5 years ago

Interesting creature!!

ScottRasmussen 5 years ago

Here's a link with some good pictures of other terrestrial planarians: They are really strange beasts!

KarenL 5 years ago

Interesting! I've not seen one of these before.

dandoucette 5 years ago

That is really strange.

Cartago, Costa Rica

Lat: 9.25, Long: -83.86

Spotted on Sep 27, 2011
Submitted on Sep 27, 2011


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