A reader in south Louisiana wrote us a question a few days ago about a black worm with a brown underside that he found in his backyard. The worm is about three or four inches (seven to ten centimeters) long, and its body is flat. The reader was wondering what type of worm he found, and if it is parasitic. The latter concern is connected to his dog, who has had issues before with worm infections. We’ll do our best to address both issues, which are of course related.
Some time ago, a reader wrote to us to ask a blessedly straightforward question: why are planarians and flukes called flatworms? Taken one way, this is the simplest question imaginable: planarians and flukes are called flatworms because they are flatworms (just as, say, trout and salmon are fish because they are fish). In other words, both planarians and flukes are simply members of the phylum Platyhelminthes, which are more commonly known as flatworms, and that’s why they are called flatworms. We suspect, however, that our reader wasn’t driving at such a simple question. Instead, we suspect he meant to ask why any flatworm (planarians, flukes, or otherwise) is called a flatworm. And so, without further ado, why are flatworms called flatworms?
A reader from South Africa (Durban, South Africa, more precisely) wrote to us about two hammerhead worms that he found in his home. He was wondering if hammerhead worms are harmful or dangerous to animals or babies, and he was also keen to discover what is causing them to enter his home. So, the question before us is this: are hammerhead worms harmful to humans or animals (like pets), and how do you get rid of hammerhead worms? (Technically, the reader didn’t ask how to get rid of hammerhead worms, but he was wondering how they got into his house, and in answering the latter we also answer the former.)
Flatworms, sometimes spelled “flat worms” (in defiance of the standard spelling, we might add), are unsegmented, bilaterian (their bodies have bilateral symmetry), soft-bodied inveterate animals that belong to the phylum Platyhelminthes. They have no specialized respiratory or circulatory organs, and they lack a body cavity. Through the process of diffusion, their flattened bodies (hence the name “flatworms”) absorb oxygen and nutrients. Because of these biological features, flatworms are considered very simple animals.
If left untreated, worms in the human body can cause everything from anemia to rashes to weakness. And according to CNN Health, an adult tapeworm can live up to 20 years and grow up to 50 feet long.
If you noticed a white speckled worm writhing or darting around in your soil or in a body of water, chances are it was a flatworm. This thin creature may look complicated, but flatworms are actually the simplest of all worm groups.
While the flatworm is considered the simplest of the worm groups, there is nothing simple about getting rid of them if you have an infestation. These pesky creatures reproduce at an alarming rate by simply splitting in two. There are no mating rituals and no eggs to hatch. When the flatworm splits, it immediately forms a new flatworm, and so on and so on, until you have thousands of flatworms in your system. This means that the flatworms may be feeding off of your fishes’ skin and eyes, so all of the fish in your system will eventually die.