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variable per species. Marine species are often brightly colored


animal material and organic waste, parasitic species live on blood and other body material; some species can go for a year without food


sexual and asexual


when damaged or even cut in half, the loose parts regenerate into a new worm. Some even reproduce in this manner

  • Dut: Platwormen
  • Lat: Platyhelminthes
  • Eng: Flatworms
  • Ger: Strudelwürmer


There are a total of around 20,000 species of flatworms, some of which live in the sea, others in freshwater and some of which are parasitic. As the name suggests, flatworms are flat and relatively broad. They are primitive animals, but have a definite head and tail and a developed nervous system. The body and reproduction deviate so much from other worms that they have been categorized separately. The larger species glide through the water just like snails. Despite the fact that they are primitive, these animals are capable of learning. For example, they reacted to a lamp in experiments and can also learn to react to it always in the same way.

  • Distribution and habitat

    It is unknown how many species live in the North Sea. One known species is the white flatworm, a large beige-white flatworm with brown stripes. Around 70 species of flatworms in the Netherlandsare found in fresh water. Most species live in tropical waters.