Earthworms don’t have wings like a bird, scaly skin like a reptile or six legs like an insect. They are not mammals, reptiles, amphibians, birds or insects, so what are they?
Animals can be divided into two categories: vertebrates (animals with backbones) and invertebrates (animals without backbones). Worms definitely don’t have a backbone or any bones in their slender, tender body so worms are invertebrates.
The classification of invertebrate includes many animals such as spiders, insects, centipedes, slugs, snails, millipedes and even jellyfish and squid.
When I say worm, I am usually referring to the common earthworm (Lumbricus terrestris) found in yards and gardens. There are other types of worms such as flatworms and roundworms which are classified differently. The common earthworm is considered an annelid (Phylum Annelida) because it is a segmented worm with rings and segments on its body.
Other animals such as silk worms, glow worms and inchworms have worm in their name because they resemble a worm but they are not annelid worms.
So whether you call an earthworm an invertebrate or an annelid, either will be correct.
Originally posted April 2020. Updated February 2024.
I like your science
for just over 20 year i have walked on the same trail every day. Always, after a rain, many worms appear. Last year I noticed that there were fewer worms. This years there are NO worms. I am alarmed at this development and would like to bring it to the attention of the proper person(s). Who would that be? thank you –