“What is this little guy?” asks Valerie in her submission regarding the black, worm-like critter pictured below. “About 4-inches long, needle thin, in the muddy bank of a river in the Shenandoah Valley of Virginia.” To start with, we want to thank Valerie for the excellent photo and video she sent in. The video captures the sporadic, twisty movements of the worm, and the picture gives us a good sense of scale, showing us how long this worm really is. Based on this information, as well as the context Valerie provided, we think that she found a horsehair worm.

Horsehair worms are nothing to be frightened of, contrary to urban myths on the internet about these guys infecting people and taking over their lives. These guys are parasites, yes, but they only infect insects, and even some crustaceans. All human cases are a result of that human ingesting an infested insect, thereby accidentally contracting the horsehair worm, which eventually either gets thrown up or passes through their stool, without causing any serious or permanent harm. You cannot really classify as horsehair worms are either marine or terrestrial worms: they are a bit of both.

They lay their eggs in bodies of water. The eggs then hatch into larvae, which an insect drinking the water will ingest. The larvae then grows inside the insect host, feeding off its nutrients as a parasite does. Once it is fully-grown, it will burst forth from the insect, killing it in the process: similar to the trope of a hero in a fantasy story having to crawl inside the monster to slay it from the inside, causing it to explode. Once the horsehair worm is free of the insect, it will roam the land in search of a mate to repeat the process. It could be that this is what the horsehair worm Valerie found is doing. That said, since she found the worm by a body of water (the river), it is more likely that this horsehair worm has already mated and was laying its eggs in the river. In any case, Valerie needs not worry about the worm, and can leave it to its own devices.

In conclusion, we think Valerie found a horsehair worm on the muddy bank of the river. They are violent creatures, but nothing for humans or mammals in general to worry about. We hope this helps, and we wish Valerie the very best.

Summary

Article Name

Needle-thin Worm on Muddy River Bank is a Horsehair Worm

Description

"What is this little guy?" asks Valerie in her submission regarding the black, worm-like critter pictured below. "About 4-inches long, needle thin, in the muddy bank of a river in the Shenandoah Valley of Virginia." To start with, we want to thank Valerie for the excellent photo and video she sent in. The video captures the sporadic, twisty movements of the worm, and the picture gives us a good sense of scale, showing us how long this worm really is. Based on this information, as well as the context Valerie provided, we think that she found a horsehair worm.

Author

Worm Researcher Anton